I got a US-based Unionpay card from ICBC USA. This was in the days when DCC (look it up if you need to) was rampant in China. My experience has been that Unionpay cards issued in the US are just like other US-based cards: pretty useless in China.
I also have a Discover card. Discover uses the same payment network as Unionpay in China. It's also pretty useless in China.