Sets are super useful for all sorts of stuff where you want the datatype to guarantee there is only one instance of a value in the collection. UI components where you are incrementally adding things to a selection is a great example.

It’s a completely standard feature in many stdlibs and has nothing to with turning JS into a database.

It does seem like things are getting slowly better in the sense that, ten years ago, this post would probably end with them being completely ignored or receiving some kind of legal threat. But it would be much nicer if companies could just stop. leaking. personal. data.