It's mostly a different approach to "editing" a transaction.
With a blockchain, you simply go back, "fork", apply a fixed transaction, and replay all the rest. The difference is that you've got a ledger that's clearly a fork because of cryptographic signing.
With a traditional ledger, you fix the wrong transaction in place. You could also cryptographically sign them, and you could make those signatures depend on previous state, where you basically get two "blockchains".
Distributed trust mechanisms, usually used with crypto and blockchain, only matter when you want to keep the entire ledger public and decentralized (as in, allow untrusted parties to modify it).
> With a traditional ledger, you fix the wrong transaction in place.
No you don’t. You reverse out the old transaction by posting journal lines for the negation. And in the same transactions you include the proper booking of the balance movements.
You never edit old transactions. It’s always the addition of new transactions so you can go back and see what was corrected.
> With a blockchain, you simply go back, "fork", apply a fixed transaction, and replay all the rest.
You're handwaving away a LOT of complexity there. How are users supposed to trust that you only fixed the transaction at the point of fork, and didn't alter the other transactions in the replay?
My comment was made in a particular context. If you can go back, it's likely a centralized blockchain, and users are pretty much dependent on trusting you to run it fairly anyway.
With a proper distributed blockchain, forks survive only when there is enough trust between participating parties. And you avoid "editing" past transactions, bit instead add "corrective" transactions on top.
With a blockchain, you simply go back, "fork", apply a fixed transaction, and replay all the rest. The difference is that you've got a ledger that's clearly a fork because of cryptographic signing.
With a traditional ledger, you fix the wrong transaction in place. You could also cryptographically sign them, and you could make those signatures depend on previous state, where you basically get two "blockchains".
Distributed trust mechanisms, usually used with crypto and blockchain, only matter when you want to keep the entire ledger public and decentralized (as in, allow untrusted parties to modify it).