American Express Membership Rewards - Pay everyday purchases with points

Hello !
I notice that on the account services we have a link that gives us the possibility to pay with point for our everyday purchases, i've got with the US amex about 23k of points, I have several items bought in the US, but when I'm trying to use my points for everyday purchases, the system say that I do not have any eligible purchases ...
so my question is, what kind of purchases can be redeem for points ?

The redemption value is terrible. Here are some examples from my account.
Office Max $14.88, points required 2480
Walmart $41.40, points required 6900
Chevron $25.79, points required 4298

I will never ever use this feature, my boring Chase card at least gives me 1% cashback on all purchases.

what a bad redemption!! thank for this information!