It's just a nip-05 service and it literally says that nostr.com has commercial features below the "My Nostr Identity" button:

"Nostr is a protocol; explore the GitHub or visit nostr.org to learn more. Nostr.com has commercial features."

They also seem to use "Von Restorff effect" on the buttons to get users to click on the buttons taking them to nostr.org or the github repo instead of the nip-05 service or their shop.