Martin Heidegger said “Philosophizing is to ask the question ‘why are their beings instead of nothing?’

This question is a refined version of Gottfried Leibniz’s classic question, “why is there something rather than nothing?” and Heidegger is on the right path to ask rather about the existence of ‘beings’ than merely ‘things’, but he does not go far enough, he merely refines the question, he does not ask a new one. Stopping on the right path is not the same thing as reaching the right conclusion.
His refined question is significantly better than the original because the answer to why there is something rather than nothing is already answered by the existence of a number of inanimate forces and systems: chemistry, time, matter, gravity, etc. These alone answer Leibniz’s question quite convincingly, although they give no indication of the cause of their own existence. The only significance of Leibniz’s question lies in the fact that a person, not just a thing, is asking it, which is brought into better (though incomplete) focus by Heidegger’s question.
Without that fact it is a meaningless question because mere matter under the blind direction of inanimate forces would never have asked it, and yet there it is, it has been asked.
Leibniz’s question is too small for the questioner to be asking it, and therefore, it is not the primary question. It’s like a man asking himself that if he were a tree would he prefer to be a beach or an oak, or if he were a mountain would he prefer to be in the Rockies or the Himalayas. The question is meaningless, because if he were a tree or a mountain he could not ask it.

Heidegger is right in two accounts, that the appropriate question is “why are there beings?” Although a better question would be; “why are there beings instead of just things.” Secondly Heidegger is right in referring to ‘beings’ instead of ‘being’. That may seem an obvious point but it must be mentioned that a significant portion of the populations holds to the faith that plurality is an illusion.
But the problem is a lot deeper than merely a difference between ‘being’ and ‘thing’, because simply ‘being’ is also not enough existence, on its own, to warrant the question being asked.
The question must be asked by a person, because only persons have the capacity to ask questions. What you must have, in order to ask a question, any question; is self-awareness or you could call it personality, and it helps if you have some intelligence, although personality is the prerequisite; a knowledge that you are not other things, other beings and other people, and that they are not you.
Now Heidegger’s question is like a man asking himself that if he were an animal would he prefer to be an elephant or an bear. The question is also meaningless, because if he were merely an animal being he also could not ask it, no matter how intelligent.

Now I’m hoping that you notice here that Heidegger’s question is, nonetheless, more advanced than that of Leibniz, and yet is a more fundamental question than Leibniz’s question. The reason for this is that Heidegger is asking about the more necessary object: “Being”, while Leibniz is asking about the less complex subject: “Thing”. As Alan Perlis said: “Simplicity does not precede complexity, but follows it.” And so, in this case, as in so many, the simpler question is both more fundamental and more advanced, at the same time.
It may be clearer for you if you were to look at it from the other end: Since we have all been children it is easy to show that a child asks questions about her parents long before she asks questions about her things. That is because her things are not people, but her parents are.
Now if you were to think about it you will notice that the most necessary object is “Person”. In every sense, person is at the root everything. Before we can ask about things we must ask about beings, but before even beings, we must answer the questions of personal existence, not just because we are people, but because only people can ask.

To use a popular example, The Architect would have known (although he must have kept it to himself) that Neo’s fundamental problem was not “choice”. Choice may be a fundamental problem, but it is not the fundamental problem. More fundamental than choice per se, is the ability to choose. Without the ability to choose Neo’s choice would cease to exist.*
In essence he expresses the problem by asking, “why must I choose?” But a better question would be, “why am I able to choose at all?
Or one could pose it this way: Neo’s subjective question, “what is my choice?” And the objective question he ought to have asked, “how is that that I have the capacity to choose in the first place? Since it is only that capacity already in me that the machine is manipulating.” Here we are dealing again with an attribute of the the object of person, this time compared with the subject of choice.

Now it seems to me that to carry Heidegger’s train to it’s logical conclusion would cause us to ask a much more fundamental question, even though it is also a much more advanced one. “Why are there people and not just one person?
One could ask the same about things, “why are there things and not one thing?” and about beings, “why are there beings and not just one being?
To compare being with non-being, and to compare something with nothing, is not as fundamental, nor as urgent as to compare the existing plurality of persons with the non-existing singularity of person.

Why are there many persons instead of just one person?
Physicists conceive of our universe where all matter has eventually devolved into energy and weird positive electrons. I have some confidence in the people who develop these theories, and thereby some confidence in the theories themselves. But I am a lot more sure of the fact that they are distinct persons from myself than I am about their theories.
Now theist physicists understand a creator cause and a metaphysical effect for persons, and atheist physicists understand a physical cause and a physical conclusion for persons.
In other words when atheist physicist view the universe they image, by default, a time before people but with existing beings and things, and a time after the existence of people but still within the existence of beings, and a time when beings cease to exist and all that will be left will be matter. Whereas a theist physicist sees the existence of matter and of beings within the eternal parenthesis of the existence of persons.
CS Lewis put it this way in ‘The Weight of Glory’, “nature is mortal, we shall outlive her.

As a person I am extremely interested in which one is true. Because either one is or the other is, and it is one of those rare situations where it is not possible for them both to be false.
And the answer is not found in the conclusion, because all conclusion is, from this perspective, frustratingly theoretical. The answer, if there is one, can only be found in the origin of persons (plural) as a fact – as the only fact – of existence. You will not even find it in the origin of personhood as an idea.

*It is the direct result of the movie culture and its writers who have been trained to write punchy, emphatic lines for their characters, even if they are utterly illogical. This works by accident because so many characters are, in fact, very illogical. But it’s such a jar to the mind when the character is supposed to be a logical thinker, but his words reveal that he is not. Going into the mines of Moria Gandalf would not have said, “we have but one choice…” because that would not have been the case; they had no choice at all, unless you include surrender and suicide which Gandalf is clearly not including – or he ought not to be, his words now create doubt in his character. Tolkien knew this, which is why the original Gandalf said, “the passage is blocked behind us now, and there is only one way out.” Not as punchy, but much more satisfying! That’s a Gandalf I can trust to get me all the way to Mordor and back!