> Who cares how it's done on the bookkeeping side? I care about my account being lowered by the amount of crypto something has cost me and getting the service / goods I want.

Anybody who understands what cryptocurrency is supposed to be should definitely care about it. There is nothing crypto about these cards, they just liquidate some of your crypto collateral to settle in fiat. You could do this yourself, or use any other random credit card. It's a convenience, but is literally the anti-thesis of cryptocurrency, and/or has nothing to do with cryptocurrency in the first place. The cards are ran by a financial institute or bank and the collateral could be anything.

Sure, the card and its convenience and functionality has value. Cryptocurrency plays zero part in it. Funnily enough, what you see as value here is provided by the fiat system and not by cryptocurrency.