Hi I have a question for nostr users. Can someone please tell me what the main differences (pros/cons) are between the AT protocol and nostr. ie what are the advantages of choosing AT protocol over nostr (and separately how does bluesky compare to Nostr in terms of decentralisation/interoperability with other AT clients). Why don't nostr devs prefer to use the AT protocol?

What are zaps for, is this some kind of business model? Is it necessary, why does every single nostr client have them?