Your idea made it into 0.17: the watcher can now be addressed by its pubkey and relays instead of a domain. It runs on your own machine without a node or domain; the app sets it up from an nprofile. 

monero

monostr: a Nostr client with Monero tips instead of zaps (public beta, Android)

schmidt

Your idea made it into 0.17: the watcher can now be addressed by its pubkey and relays instead of a domain. It runs on your own machine without a node or domain; the app sets it up from an nprofile. https://github.com/schmidt1024/monostr/blob/main/watcher/SELFHOST.md