We often talk about what can be built on or with Nostr, but we don't talk about what can't or shouldn't? When it comes to the apps that I use on the daily, I don't think there's anything that Nostr couldn't be integrated into at some level. Nostr is incredibly simple. This makes it versatile.

Though, I don't think I'd want to use the same set of keys for everything though. Some applications I'd want more privacy or want to use different identities and some applications I'd want to separate the flow or co-mingling of data.