Rather than verify lets say nip05 makes your identifier distinct but readable/ memorable vs the npub which is distinct but not memorable. Anyone can create a copycat display name and PFP so without the nip05 anyone you aren't following would be difficult to distinguish.

We actually had this issue with a user who is using an AI PFP and a bunch of other people joined with that PFP to fuck with them but at least with the nip05 you can say "that's user a, that's user b etc" in a thread without following them.