Hey,

With NIP05 you make your account easier to check. Your npub is long and confusing, no-one is going to check that.

NIP05 makes it easier to read your npub by making it 'email-like'; name@domain.com. The provider links your npub via that domain to the name@domain.com. Only your account will show it as valid, since no other account got the same npub as you have.

You can pick any provider you want, and even on multiple domains. As there is no central point in Nostr you cant have one provider do this.

Best to just stick to one provider. I also own N0str-Check.com so others cant fake Nostr-Check.com (spotted to zero instead of the O?).