Second of all, abusing chargebacks when a vendor upheld their side of an agreement is a crime, and if you can prove that you delivered the goods as the consumer requested, the chargeback can be reversed. This is not a problem with the system.
The way that blockchain "solves" this non-problem is by making the transaction record immutable, so that no transaction can ever be undone, no longer how fraudulent or illegal. That's why the main users of blockchain technology these days, aside from speculators, is scammers and theives, because once you have somebody's crypto money, it is technologically impossible to ever return it to its rightful owner, even with a court order.
Theft on the blockchain has already surpassed all other financial theft in the world pre-2016. Getting access to people's keys, or tricking them into authorizing a transaction, or writing malware into smart contracts has enabled a golden age of theft that cannot be undone.
Immutability does not imply correctness.
> Unless a ledger is public and independently verifiable
You say this as if those things are connected. They are not. Your credit card transaction ledger is already independently verifiable, with the magical future technologies known as "receipts" and "bank statements".
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.