Well, yes, this is exactly how the type checkers of statically-typed languages work: as linters, during compilation. The largest difference is that typing in Python is gradual, so not everything needs to be typed as you say.

I agree that statically typed languages are preferable. I don't consider static typing optional so I'm glad Python is growing a solution that supports it, though.

In my experience, mypy works surprisingly well. It doesn't hurt my coding speed at all but enhances it to levels that were not previously possible in Python, due to a lack of typing. False positives are rather rare.