Like I said the first time, if you can afford to pay it off without paying interest why not have a points or cash back card? It just makes sense.
I have 2 cash back cards. One is a Kemba card that you ear 1% on everything but at the end of the year that balance is placed in an account that earns 10% apr and the Chase Freedom card that I get 1% cash back and 5% on whatever their quarterly "special" is.