1) Apple has issued 48 press releases YTD in 2014, all of which have a certain level of importance and noteworthiness, which stands at contrast to many other companies of Apple's size.
2) I judge an Apple press release's importance by its Apple executive quote. Apple SVP Eddy Cue in announcing UnionPay support: "The ability to buy apps and make purchases using UnionPay cards has been one of the most requested features from our customers in China" and "China is already [Apple's] second largest market for app downloads, and now we're providing users with an incredibly convenient way to purchase their favorite apps with just one-tap." I really wouldn't read much more into the announcement. Apple expects this deal will boost app purchases in China, simultaneously boosting the iOS ecosystem.
3) China is an interesting topic when analyzing Apple. Many assume that China represents untapped potential where Apple will win simply by opening retail stores and selling new product. In reality, Apple has been working extremely hard and has faced numerous challenges in China. Greater China (Hong Kong, Taiwan, and the mainland) currently represents approximately 15% of Apple's revenue. This UnionPay press release embodies one small victory that when combined with years of work will likely lead to China being Apple's largest market.