> I've never encountered a situation where the lack of typing bit me in the ass

Quite the claim! For me the moment I never want to look back to is to refactor a substantial part of the architecture of a JS app with more than 20k lines of code (And I did write most of it myself). If you don't do large scale refactorings or work mostly on smaller apps, then indeed, types won't be much of an issue.

But you should become aware about how often you see "undefined is not an object" and similar, that's a type error that is almost gone when using TypeScript.