CPFP is actually a very inefficient way of 'accelerating' a transaction.
Definitely, RBF is a much efficient way of saying "I want this confirmed", but I'm just pointing out that, even without RBF, you can still use this "bump" feature, without the danger of trivial double-spending.
For starters, credit card settlements and Bitcoin transaction finality are completely different and they cannot be equated to be the same.
They're different, but not completely different. They both satisfy for the same thing; transaction settlement. And I can compare them, from both merchant's and customer's perspective. What's cheaper for both? Bitcoin, because trust costs. What's more secure for the merchant? Bitcoin, because there are no chargebacks, bank reversal, disputes. What's more private for both? Bitcoin.
Customers won't be there to defraud you for a cup of coffee or for lunch and it really depends on the risk tolerance.
Exactly, which is why I said I would approve an unconfirmed <= $300 worth of bitcoin transaction as settled. For a cup of coffee, though, Lightning is a better solution. But, for supermarket fulled cart, that can't be easily paid with Lightning, since there's high chance of routing failure, and where there's rush, the merchant should accept unconfirmed transactions.