I think the bigger thing that’s overlooked is that nearly every item today is priced assuming the 3% fee from credit cards.

So by not using a credit card, you’re not getting the 3% cash back (or rewards equivalent) and therefore paying more.

There are a handful of places that offer a discount if you pay with cash (or rather a fee if you pay with a card) in order to make these fees clear to the buyer, but it’s becoming rare. Usually gov websites like DMV or mom/pop shops.