Seems “blockchainey” to add a token to something that doesn’t need it.

If there is benefit to the payment, like nostr:npub1h0uj825jgcr9lzxyp37ehasuenq070707pj63je07n8mkcsg3u0qnsrwx8 is doing, then it makes sense.

Otherwise, just do a Nostr key verification scheme.