What I envision is a (potentially nostr based) relay owned mining pool: the clients submit work to the pool to earn post writes. The relay owns the pool and so it can collect any mining rewards to keep the relay running. The users can benefit from this reliable relay and they can keep using it without even owning any BTC, since they only need to do some work, if needed, in order to post some shit. Spammers are welcome, since they will be basically mining for the relay :)