> Mypy catches bugs

100% yes. It’s much better than the examples would lead you to believe. Mypy catches stuff like:

    def f(arg: Optional[Object]):
        arg.method() # type error
        if arg is not None:
            arg.method() # ok

It’s half the goodness of what you’d get from a well-typed language like Haskell or Rust but with the ability to say “trust me on this” and disable type checks for a line or two. Honestly I wish go tooling checked for nil pointer use as well as mypy unwraps optional values. Every time I add type hints and use mypy I find bugs. I would never make the case that type hints are better than a strongly typed language (especially with pattern matching), but it’s a great balance when writing python.