There's a reason some of the most famous mathematicians, scientists, engineers, and philosophers of all time believe(d) in God.
The Hebrew name of God, YHWH, literally means "He Who Is." In other words, the Self-Existent One. The father and originator of all things that were, are, and will be, who exists outside of spacetime.
There are countless other religions that believe in a deity who created the universe. These deities either created themselves, or had always existed outside of space and time. To that end, any one of those deities would be on equal footing with YHWH. I don't think that it is appropriate to axiomatically claim that a certain deity exists because only that deity could have caused the universe to exist.
Why Christianity then, over Hinduism? Why any human religion at all?
[無] https://en.wikipedia.org/wiki/Trinitarianism_in_the_Church_F...
Who Created God? No one? Why does the universe need a creator if God does not?
Where does free will and evil come from if God is "originator of all things that were, are, and will be". For true free will to exist it must have a source of entropy which denotes something outside of Gods control and design otherwise everything is deterministic as set forth by God.
That reason being that for much of Western history if you didn't believe in God the Church would burn your research in a big fire and probably you on top of it.
I like to think he was referring to computation. There's a reality to the constant pi, its computation, and ourselves and the representation being part of that same universe.