I'm in Canada. My wife uses WhatsApp, and several of my friends and family members use WhatsApp too. The same is true for my wife's friends and family. I also know several people who use WeChat, but for that, it's because they have contacts in China. I personally stick only to iMessage and SMS though.It's funny, I hear that sentiment a lot - on the internet. But I've never met anyone in person in my entire life who uses either of those services; most haven't even heard of them. I suppose it's probably a regional thing, SMS is still extremely popular in the U.S.
BTW, when we went on vacation in Costa Rica, many of the local excursions (if you booked outside the hotels) were primarily booked through WhatsApp.