Do you really believe getting your own money back is FREE money?
You are choosing to ignore the science of spending. People who purchase with credit cards spend more than they would if they used cash (not a debit card). The increased spending outweighs the rewards benefits. The main underlying reason for the differences in spending is, at least, partly due to differences in the pain of paying. This is why casinos use chips versus cash at the tables.
Fraud protection? Consumer liability for debt and credit cards is limited to $50 if the fraud is reported, period! It can even be $0 for debit cards if you have the right bank. Fraud protection offered by debit cards versus credit cards is identicle as mandated by law and common practice.