> A trusted ledger is valuable, but a ledger doesn't have to be public to be trusted. When I swipe my card at the grocery store, I'm not shaking in my boots with my fingers crossed, doubting whether the transaction will be recorded as transmitted or not.

Of course, because as the customer nothing bad happens to you if it’s not. Worst case scenario, the merchant doesn’t accept your payment and you either have to pay with cash or not buy anything.

The worst case scenario for the merchant is substantially worse. If the payment doesn’t go through, they lose money. This could happen days or weeks later if the customer decides to chargeback the merchant. There are countless stories of payment processors siding with customers, placing holds on a business’s funds for extended periods of time while conducting investigations, etc.

I would actually take the opposite stance. Unless a ledger is public and independently verifiable, there is no reason to trust it at all. Nearly every instance of financial fraud has relied on people trusting a private ledger.