Try being a foreigner with a unionpay card but lacking a Chinese indentity card number. I heard it's better now, but that requirement was always a bummer for me in trying to do payments online.
As recently as last year I had trouble setting up Uber in china because they wanted my Chinese ID number to go along with my Chinese credit card. Thing is, they wouldn't ask if I was using a non Chinese card.
I have both Alipay and Baidu Wallet connected to my Uber China account. I haven't tried linking a Chinese bank card directly to Uber, but I don't have any reason to do that.
