FWIW I think an “in device relay” is a great idea. I also see the problem with having “multiple” apps to dl, when multiple clients are already a head scratcher. 

For “most” people the value prop of a “signer” app will be as an “identity manager” for accessing the entire nostr ecosystem (native apps and PWAs). Given this use case, having “personal storage” built into the actual signer app makes total sense. Il even raise the ante, and go so far as to suggest this app (the “identity manager” class of apps) could even act as a nostr on-ramp for profile building, client discovery, and relay management.

Maybe on paper these are separate NIPs, but in practice a single “this is me on nostr” app wd be bomb!