Having a Nostr Address is essential, especially if you have a significant following. 

You can use your own domain or trusted providers like Nostrpleb, Snort, and NostrCheck. 

Responsible Nostr Address providers should also enforce policies against impersonation.

It can lead to severe harm. I mean look at this these all over fake accounts.
https://i.nostrimg.com/1db6e2d015be361bfd810224a83bfb1a96bd2ac6be938b1d08ef2ca89a142b7a/file.jpg