Here is my theory. Years ago I heard people in China mentioned “Apple Phone” (苹果手机), for iPhone. This is particularly true for older generation as their grasp of English is not as good as younger generation. So this time they decided just go with Apple Watch 苹果手表.
Note this is also their fourth main product category innovation since year 2000 : iPod, iPhone and iPad. If they stick with iWatch, the name will be too predicable. But this is secondary compared to the reason above, which is use their Apple logo, and name. Both are well known all over the world.