SMS works really well in places that have poorer coverage / worse networks. That's partially because it doesn't rely on the 'data' coverage but fundamental tele

SMS works really well in places that have poorer coverage / worse networks. That's partially because it doesn't rely on the 'data' coverage but fundamental telephony technologies that have been around much longer (https://en.wikipedia.org/wiki/Short_Message_Service_technical_realisation_(GSM) https://en.wikipedia.org/wiki/Short_Message_Service_technica...). So basically if you have a signal of any kind, SMS will probably work reliably. Then there's the fact that you don't need any extra app or identity to use it. If you have a phone with a plan, you have no barriers to using SMS. Both these aspects are not as true for the software over Internet messaging solutions, and I think that's why SMS is still widely used and will continue to be widely used.