> No one uses SMS because it's primitive and limited compared to regular messengers.

You also have to take into account that SMS is 5-10 times more expensive almost everywhere outside the US. Unless you have a flat-rate plan, a single 140 character messages is about 10 cents where I live. And even if you have a flat-rate plan for domestic messages, it's 1-2 USD (per message!) when sent to friends and family abroad. I don't use SMS because it's just being ridiculously over-priced. I want my device to use data to send data, regardless of what kind it is.