Exactly. The only way for this to deliver on its goals would be for it to not be public or permissionless. And if that's the case, then it should really just be a database and/or a shared protocol between financial institutions.

Once it's truly "open", you can't have any sensitive identifiers in there, so you need another protocol/system for correlating opaque identifiers with real-world entities (thus defeating the purpose).

And if financial institutions are involved, they'll want the ability to do what they do now: rewrite history whenever they feel the need (or are compelled by governments). Another strike against using blockchain.