Lot of people in HK use Wechat (I have lived in HK). I wouldn't say it's so clear cut. LINE is also popular. But definitely Wechat is substantial especially sin

Lot of people in HK use Wechat (I have lived in HK). I wouldn't say it's so clear cut. LINE is also popular. But definitely Wechat is substantial especially since there's a lot of people from mainland and also if you got friends in Shenzen, you will use Wechat. I have seen many HK locals (born in HK, not immigrants from mainland) using Wechat.