works with uber cash just fine. you just have to use amex plat/gold/green as the default CC payment source. if youre strictly using amex credits only, then its not a big deal, but you still have to pay any overages with the amex. for most people who just want to use their monthly amex credits, its not a big change. but lets say you have $5 uber credits left and your meal is $20. you have to pay the extra $15 with an amex plat/gold/green. you can no longer use another CC to get the UEP discounts. for some, thats huge because of free delivery. and what if you only have plat? thats 1x for food. that would suck.