Not because mypy is bad per se, but it just doesn't flow into a Python workflow naturally. Every time you try to interact with an external module without these annotations you immediately lose all the advantages of statically typed programs.
For me, Python with annotations just doesn't make sense, at that point I would prefer to program in Rust or Java.
Type annotation and mypy, while better than nothing, is a hack and doesn't always properly work so in a real codebase you'd be using `# type: ignore` quite often even if all of your downstream code is properly type-annotated and mypy-typechecked.
Most importantly though, it does not make Python statically typed, by no means. It just lets you lint stuff in a semantic fashion (which is helpful, no doubt), improves auto-completion and removes the need of listing type requirements in docstrings.
