The power of a notary is that someone is legally verifying the state of the document under penalty of perjury. In this case, you don't trust the party doing the verification, by definition, and there's no second party, so I don't see what this solves.
That there is an immutable log of the events is an implementation detail and could be solved with a write only DB completely independent of blockchain.
That there is an immutable log of the events is an implementation detail and could be solved with a write only DB completely independent of blockchain.