npub may be your "username" but it's not your handle. it's not what you want to be referred to as on the network. there's the extra step of setting that up.
setting up an account and making it yours is a hurdle.
Even setting up a profile pic was a pain cuz I had to upload my image somewhere else first. I haven't even bothered with my banner.
nostr is easy to use once you know how to use it but getting there is still clunky.