Choosing the first few characters of your pubkey accomplishes the same thing. It doesn't matter if other people can generate the same thing, that also applies for NIP 05.
Discussion
It's similar, but NIP-05 also has the provider verify it's indeed you by having a file that links your npub to the you@theirdomain.tld.
If I change my NIP-05 to aspartame@nip05.social, clients won't show me with a verified tick, because when they check with nip05.social, aspartame@nip05.social is linked to a different npub than mine.
But each key is also unique, so I don't see the difference, aside from the check mark.
It's just easier for people to see a tick and recognize the bla@bla than it is for them to remember this: npub17e6l6tp789hwwnugm3l6zmgfffh369lv08yfuwj452hflhc530xq36epc7.
Once wider adoption happens, it will also help organizations verify that it is indeed them by having NIP-05 off their own domain (e.g. Google could be google@google.com)
Anyone could generate something that looks like npub17google789hwwnugm3l6zmgfffh369lv08yfuwj452hflhc530xq36epc7
True, NIP 05 is better for an actual important person, but that's not how anyone is using it rn.