The credit card interest on my cards are obscenely high and I do not care. I pay them all each month and do not accrue a penalty. In the credit card industry the call us “DEAD BEATS” because we pay our cards on time with no penalties.
In my Antique shop we always give a discount for those that pay cash or by a local check. They get what the credit cards company would have gotten by only shifting electrons in their payment system that cost them little. Actually, we give them more than the credit cost to us. It is good business. They come back later to buy more.
Banks are not your friend but a necessary evil, as most of our sales are by credit cards.
I do exactly what you do. I got the highest percentage cash back credit cards I could find. Then I started charging everything I could on the cards and set my bank account to pay the cards off in full every month. I just reap the cash back at no cost to myself.
The rewards aren’t huge, but if I can save 2-3% on my expenses, why wouldn’t I do that?