Fraud protection is inherently better for credit cards, because you haven't spent your money. The bank has spent the money, and you don't have to pay the bank if someone defrauded the bank. So the bank has every incentive to get the money back. Not so with debit. You spent your own money.

That cash back is basically a scam. It's paid for by the credit card processing fees - fees which are charged to merchants and ultimately get passed on to the customer in the form of higher prices. Some merchants even tack on explicit ~$3 transaction fee for credit card purchases, to cover transaction costs.

So the cash back is just a partial refund on your credit card processing fees.

But once the scam has permeated the system, it's to your advantage to participate, because you pay either way.

Every study shows that people spend more money when using credit cards than when they pay cash. It helps the merchant.

Cash also has cost - employee theft, risk of getting robbed while taking it to the bank, it takes more time to handle, etc.

If I had a business, I would not accept cash at all.

In Europe they have debit card with the same level of fraud protection - and without credit.