Damis is just one app using the Nostr protocol. You can see on Damus also people using all other Nostr apps and vice versa. So yeah, there are 🙂

Actually, approx 500k keypair exists on #nostr, but 9-10k user is active (a lot of them from the Far-East, but I can't read nor write Japanese, Mandarin or Korean 😊 )