Apologies for the late reply to your question.
As for your answer; WeChat in an area 'off the beaten track' you'll find girls with ease as they're not surrounded by girls that are working in the tourist traps.
For example when I was in Mindanao. The girls on the app were simply local girls with everyday jobs/careers who haven't found themselves drawn into the bar scene etc. But as is the case Asian girls have a natural curiousness about 'Western men'. WeChat simply is an ideal conduit of introducing the two.
However, in the big cities; in my case Manila, Kuala Lumpur and Bangkok - WeChat has been discovered by WG's, bar girls, masseuse etc and they advertise on the app not unlike Craigslist etc.