If the relay's admins decide to delete his database? I know, maybe your data is in other relays, but, and if you post in exactly one relay that the relay's admins decide to delete?
Discussion
Probably gone forever.
This is why we run our own private relays. It's anti-rug technology.
I understand, but the most people that use Nostr protocol in the massive adoption will not run the own Relay. Maybe exist in the future a database like a service, where the user pay for a relay's admin stock your data with a contract, ensuring the integrity of your data.