Something I'm trying to understand, a regular nostr post always goes as nip-01. Then if I want my small posts to go as long form I've to force it to be nip-23 by specifying the "kind". Is that right? Then when would someone use nips-13 to show proof of work? If it is meant to combat spam, won't the bots spreading spam always use nip-10 or nip-01 as "kind"?