The missing feature for docs is now GDrive, ie organizing and cataloging your artifacts to build a coherent long-lived KB. But for that you can still export.
Anthropic added a while back the ability to let clients provide their own API key, again I think that’s under-explored and will become more relevant as AI gets more penetration.
Building out quick SPAs, HTML pages, etc is a great use, I think the innovation will be making these things supportable and usable for more than one-shot single-user artifacts. Eg user login, analytics, etc.