NIP-05 is an easy way to provide a proof as to your identity. It does not prove that the identity is trustworthy.
Generic NIP-05s are fairly worthless since you’re not in control of it. If you use a domain you own, for the NIP-05 @btcpayserver supports this) it will add a lot more credibility (but will doxx you).
NIP05 does NOT prove identity, if MOST (or any FTM) users are simply buying them from vendors. It validates nothing.
NIP05 only asserts the uniqueness of an arbitrary human readable username. Nothing more.
You can prove owning a domain, thus prove *an identity*. That’s what I meant. But you’re correct - it does not prove who you are.