More of an acceptance issue.
My best unionpay earns 1.3 miles per usd (roughly 1.67% if I use a 1.28cpm valuation). Unionpay is usually 1.5% cheaper than fubon visa (below) except in Macau and China where it's 2%

Fubon v/m earns double miles (3.33%) overseas

So it's a wash. I didn't bother pulling out the unionpay in france.