nostr:npub1h0uj825jgcr9lzxyp37ehasuenq070707pj63je07n8mkcsg3u0qnsrwx8 has pioneered one of my favorite use cases of Cashu today, which is to pay for access to a a nostr relay with ecash. 1 event = 1 sat. 

They achieve this without accounts or registration. Your balance is not tied to your identity. You can post from any pubkey. If you want your real sats back on Lightning, you simply burn the ecash with the mint. The next step would be to run their own mint for their relay.