Credit cards are a high powered tool and like every other power tool they need to be used correctly and with care....
Every time you use a credit card the business you are paying with your credit card pays a small percentage to the clearing house, which in turn pays part of that money to your credit card company. That is one way they make money but the way they make enough to buy your airline ticket is simply put. They charge outrages interest and if you pay 18% annual compounded daily and they are giving back 1% one time and they charge the 18% until you pay it off, they are coming out ahead and you probably already knew that.