I know sometimes performance doesn’t matter, and python is certainly useful, but it’s not fast. It can be fast enough and they’ve put a lot of effort into making fast libraries (called in c).

When doing bioinformatics we had someone update/rewrite a tool in java and it was so much faster. Went from a couple days to some like 4 hours of runtime.

Python certainly can be used in production (my experience maintaining some web applications in Java would make me reach for python/php/ruby to create a web backend speed be dammed). Python has some great libraries.