Eh. I don't use typing tools for most things because (and I know this isn't a popular opinion even though I believe it's the correct one) they rarely save you from real world problems. They are mostly useful for auto-complete in your IDE, so you have to weigh the time you spend annotating your code to help your IDE auto-complete function signatures vs the time the auto-complete saves you. I think that if you use this as:

    def foo(bar: list):
        print(bar)

that type checking will be happy.

If you use it in conjunction with mypy it definitely saves you from alot of real word issues. In addition, it is also an amazing way of documenting an important element of your code. And annotations van be used by modules (like pydantic) to get even more use. Improvement to anotations have been the biggest improvement in python since 3.6 imho.

What kind of bugs have you encountered in practice that were caught by mypy but not at runtime, manual, or automated testing? I am genuinely curious because in my experience the only time I have seen this is when you either transpose the order or arguments to a function (detected the first time you run it) or if you pass None when an actual value was necessary (detected the first time you run it).