The trade off is pretty much a no brainer from a production standpoint. In exchange for including some Chinese cast - cast always being a secondary concern in these films anyway - and shooting in some Chinese locations, the producers get direct investment from China Movie Channel and Jiaflix Enterprises while also guaranteeing that the film can be released wide across the country without the hassle of having to be selected as one of the limited number of foreign productions allowed in via the restrictive import laws.
Sure, the China Movie Channel is a government organization run directly by SARFT - responsible for film censorship, among other things - but, hey. Nobody seems to watch these things for story, either, so it's not like it really matters what requirements may be placed there, right?