I like nostr:npub15dqlghlewk84wz3pkqqvzl2w2w36f97g89ljds8x6c094nlu02vqjllm5m's suggestion to bring digital scarcity through #Bitcoin and orange check where you verify your profile through a (potentially larger) transaction at the beginning.

Paying for each message at @SN is interesting. I wonder what would be more effective but also accepted by real users.