What are the functional advantages of the Chinese version? I have both (Chinese on one phone and English on another), and was unaware they were different (or any more different than 微信 v WeChat). And, I've never seen any discounts on the Chinese version that would work for me or 90% of my Chinese friends (I don't know many party members).

​​​​​​I'm also curious why you prefer 12306 over ctrip. I usually use the former to avoid paying a (tiny) booking fee, but if I wasn't already registered or didn't take trains often, I wouldn't bother with 12306 because I prefer ctrip's UI and customer service.