This reminded me of Keybase where they signed and published [0] their root Merkle tree to the Bitcoin blockchain, as part of their server security mechanism. It was an ingenious idea at first until when it came to signature revocations. Even though they have the mechanism for that too, the data itself is still stored onto the blockchain forever with no "garbage collection" on deprecated data, outside of Keybase's control.

[0] https://book.keybase.io/docs/server/merkle-root-in-bitcoin-b...

[1] https://keybase.io/docs/server_security/merkle_root_in_stell...