I like the idea of a built in email.
I’m more of a Lens user, but with their recent upgrade, a lot of functionality has been lost(temporarily I hope).
Anyway, like nostr, Lens is a protocol build for social interaction. To me, this means that chat, email, short messages(like you mention here), and places to share media are necessity.
I’m a writer, and I don’t have the time to set up a dozen apps for everything I need, but nostr could easily handle a large portion of my needs.