Personally I haven't felt like Typescript has bought me enough over JavaScript to use it in contexts that I don't have to. I have to use TypeScript for work, and it's "fine", but I guess I haven't found that it helps all that much.

I'm not sure why; I guess it's because the web itself is already really flexible that I find that the types don't really buy me a lot since I have to encode that dynamism into it.

To be clear, before I get a lecture on type safety and how wonderful you think types are and how they should be in everything: I know. I like types in most languages. I didn't finish but I was doing a PhD in formal methods, and specifically in techniques to apply type safety to temporal logic. I assure you that I have heard all your reasoning for types before.