The issue is that, often, without type annotations there would be no cyclic dependency (because any type matching the implicit interface would work). So by intr

The issue is that, often, without type annotations there would be no cyclic dependency (because any type matching the implicit interface would work). So by introducing type annotations (which means extra imports), you end up having to refactor quite a lot of code and the end game is a one-type-per-module-with-separate-interface-definition system of the sort encountered in, well, statically-typed languages. If you don't do this you end up with the 'Type in string' annotations mentioned in the article and TYPE_CHECKING-gated imports. Both of which feel kind of hackish. It's fine to have implicit circular dependencies in Python because duck typing means that every function is effectively generic. Type annotations eliminate this and turn Python into a fundamentally different language. Type annotations aren't just extra boilerplate in function signatures, they also have these sorts of knock-on effects.