I have noticed that when I use my credit card to buy gas, groceries, and items, that it will ask me at the register if I want to use any of my rewards points. In every case, be it Walmart, Amazon, or the gas station, its redemption value is awful compared to redeeming the points for cash value from the credit card company. They all offer a 1,250 = $10 rate, when at the credit card website, the conversion rate is 1,250 points for $12.50.
I pay for everything through one cash rewards credit card. We use that money for our vacations and certain special purchases. My wife got her new Tablet for free with her points proceeds as well as our last vacation.