I don't think this US based Unionpay is useful unless you make frequent trips to China.
It is theoretically interchangeable with Discover yet it is rather troublesome to use in practice. Many POS, which accepts Discover, reject it while many establishments won't accept it when chip authorization fails. It only works through Discover network using magnetic swipe and only for certain POS. It doesn't work online, for websites accepting Discover, either.
Based on what
Scifience posted, it is not fully interchangeable with local issued Unionpay in China either.

I am not sure if it is worth the hassle.