A Julia user knows more about Julia than a Python user knows about C.

So more people knowing C than Julia somehow makes it easier for me? Absolute nonsense.

They do, what's your point.

My point is that there are far more C programmers and C code in the world than there are Julia programmers and Julia code. This is the advantage of Python: it was able to leverage billions of lines of C code by simply acting as a glue language.

But I don't know C, and it's easier for me to be able to write fast code in a language I actually know.

Having to switch to a language you don't know is not a good situation, it doesn't help that a lot of other people know that other language.

Just fyi, Julia has a fantastic and very fast C foreign function interface, just like Python.