Correct, but all of this only works if: 1. you send your notes to wss://lockbox.relays.land/ using the NIP-70 protected "-" tag (Jumble does it automatically when you manually select lockbox as the relay target); 2. you don't send your notes anywhere else; 3. lockbox is in your "write" relays list so others can try to fetch your notes from it (otherwise they will have to manually visit lockbox to see them). There is a nicer standard coming up that maybe will make these things simpler and smoother for everybody (and lockbox will die):

GitHub

exclusive/paywall/premium content by fiatjaf · Pull Request #2156 · nostr-protocol/nips

https://github.com/nostr-protocol/nips/blob/685ddacdbf7f3c7684a362c96129130241433723/63.md