Comment by bjackman

I think you're forgetting how easy type annotation is.

I occasionally spend like 2h working on some old python code. I will spend say 15 minutes of that time adding type annotations (sometimes requires some trivial refactoring). This has an enormous ROI, the cost is so low and the benefit is so immediate.

In these cases migrating code to a proper language and figuring out interop is not on my radar, it would be insane. So having the option to get some best-effort type safety is absolutely fantastic.

I can definitely see your point, it's a useful analysis for projects under heavy development. But if you have a big Python codebase that basically just works and only sees incremental changes, adding type annotations is a great strategy.