I'm sorry, but I just don't see it at all.

Why do you care how fast your language is, if it's fast enough to accomplish your tasks within a fraction of a second?

And for numerical calculations, we use numpy, which is as fast as C++.

C has been around for 50 years and is faster than Java, Python, or Javascript, and always has been. So if speed is of primary importance, why is C such a niche language?

And which are these Python libraries we are required to use with a 0.x version? Python is over 30 years old! numpy is over 15 years old. Flask is 18 years old. Django is "only" 12 years old.

Finally, maintaining large codebases in any language is hard. In my experience, Python is considerably easier than most. You try maintaining a large C++ codebase where just compiling it takes five minutes...