Also realised bisq sort of does this but not really!!
Discussion
This is really just Bisq and RoboSats onto an open protocol and an open liquidity pool. Instead of pure P2P it becomes a Nostr relay based architecture. The problem with pure P2P is it requires the peers to be always on - this makes mobile usage impossible.
The problem Nostr solved is allowing relays to just be a dumb information hub as so things won’t be centralized, but still allow clients to come on only when the user demands - which is critical for mobile usage.