I mean by useless is it's so slow you can't make games or even big projects for GUI, only you can do is AI/ML, Data Science, and basic stuff. I think Rust is better because of its speed and language capabilities?
Python itself is just a program written in c, every time you do len(string) you are calling out of the python interpreter into compiled c code. The distinction between python wrapped c library and a python lib can be fuzzy.