So there are no fees whatsoever on your cards? You don't pay one extra cent? No transaction fees, or yearly fees? I don't see them issuing fee free cards, how will they make anything?
I'll stick with cash, it works for me.
If you know how to use them and what cards/deals to get, that's exactly right.
They count on people carrying balances. Don't carry a balance and you're not going to pay the interest. Don't use cards that charge a fee to have the card. I make one major exception--American Express. Yes, it's worth it to me and has pulled my ass out of the sling a few times when I've had problems with a merchant, services, or a product. And that's the something that's really worth examining, because this is the one reason why I use my credit cards, to protect
myself in a way that using cash will never allow.
With cash, once you hand it over, if the product or service is not what you expected, how easy is it to get your money back? If it's lost or stolen, does your cash come with replacement insurance? If you don't travel then I suppose you don't have to rent cars, but I do travel and have been renting cars since they allowed me to at age 25.
Each method of purchase has its advantages and disadvantages, Hester. If you lose your wallet full of cash, whom can you call to prevent its being spent? Lose your wallet full of credit cards, and if you have things set up right, a single phone call freezes all cards, no loss to you except the time it takes to get them replaced (at no charge).
(They barked 24/7, and I tried speaking with them about it on two different occasions. They told me they want the dogs to bark. 
)