You're forgetting that depending on the bank, you can get discounts of 10% or more when shopping at certain places. This is their alternative to higher cashback rates.

Also, Shinhan Bank China gives 0.8% back on its debit card.

In addition, Discover is very touchy with foreign transactions. My experience was the card got blocked at least once a week even with advance notice.

(one more thing- it works in mainland China only, so buying anything in Hong Kong with it is a no-go)

-from an American who lives in China and has a Discover and a Chinese credit card