Customer protection- credit cards allow you to reverse charges on defective or fraudulent purchases if you are unable to find recourse with the vendor. They usually side with the cardholder as long as a basic paper trail of a good faith attempt to resolve the issue with the vendor is included.

Also, credit cards often include insurance on purchases. For example, one of my cards will reimburse my hotel/car rental/plane tickets in certain cases of trip interruption if I purchase those items on that card.