It’s not necessary but if you want you can use one.
Discussion
How can I get one? What is the best thing about nostr?
You can check in places like
nostr:npub1k86anutkqszjqz8tv4zu9curnqw2p0qz7zfes6zc8fcfdjzgzukslph7gp
nostr:npub1zdr58j526qsrkdjhcg9xs60xfutqeey2ucugms04efnlx3spnmns2eqha9
The best of #nostr you can read it here
nostr.com