Some sites want to ship small bundles to the client by default, sourcemaps enables that + you get to introspect it because it's downloaded only when requested. Literally best of both worlds :)

Idk why you are getting downvoted.

To elaborate on your comment, if you just ship sourcemaps in production, that means you can ship minified code and track down what _actual_ source that you _aren't_ shipping to users is getting called, is in stack traces, etc.

I'm not aware of a point of sourcemaps otherwise.

Yep, sourcemaps are essential to get usable error stack traces, and that's their only purpose.