you need to work on big project for these flaws to become a problem. Say, you have a huge code base, 100000's of lines that you didn't write. Then you want to refactor a method's name. Python can't give you any guarantee the refactoring is fully complete. Only a real typed language can do that.

I write 95% of my code in python, I love it, it's my go to language for many things. But for huge code base which I don't master, the lack of type system makes me more than nervous.