The fake @jb55 could still stand up a valid NIP-05 using a different address and then put your domain in the profile. That’s why you need the triangulate with the DNS TXT record (in a way, this is a continuation of the argument I’ve been having with @fiatjaf for nearly a year except I hadn’t thought of the fake Nostr handle issue until now. ) FYI we met very briefly at Bitcoin 2023 and I was going on about adding NIP-05 npub to DNS then.
(Yeah, I’m *that* guy)