Doesn't work when majority of users are on battery powered smartphone and scammers have botnets and data centers. Pay by lightning makes more sense on a smartphone
Discussion
This is just for registration, you only need to do it once.
Or pay for PoW from mobile, for any event: nostr:note1qqqd3xhsuvz2xnvacr3rva3x85p0xt40rcxwxpvm4uk8xly4tc7s5m8g0d
Yes scammers have botnets, but they'll only use them when it's economically viable. But if it's economically viable to mine PoW for spam, then:
1) it's also profitable for honest miners to sell PoW (e.g. in a marketplace), because there is now economic demand for PoW
2) relays can add a number of cheap defenses that makes spamming exponentially more difficult, even for spammers with botnets: for example, AUTH with PoW (one time per session), then post without PoW
100% agree. It's all about not looking like an easy tasty target for botnets. There's plenty of other fish in the sea for them to lose their time.