It's also great for scaffolding CRUD sites. I used it a while ago on a MERN stack project in order to loop over a directory of game files -- Stepmania simfiles if anyone's wondering -- cleaning them up, parsing their metadata, and then POSTing it to my Express server. While I didn't avail myself of its CSV/YAML/etc parsing (JSON was a builtin and is now a third-party library), the stdlib's walk function made this generally painless.

And to top it off there's yet another bonus to this approach: having Fetch included out of the box enabled me to mock out what eventually became my frontend requests, by running them headlessly and worrying about the form logic later.

I haven't actually gotten to using TypeScript with it personally (it's among a few things built into Deno that I've been meaning to try now that I can run them with zero config), but when writing JS I've found myself reaching for it in some of the same scenarios I (anecdotally) see people point to for Python -- bulk file manipulation, scraping, programmatic requests, etc.