Its both universal _and_ relies on the voice network rather than the data network (if the device even has one). SMS is a fundamental part of the GSM spec, has b

Its both universal _and_ relies on the voice network rather than the data network (if the device even has one). SMS is a fundamental part of the GSM spec, has been for over 30 years, and is one of those super lightweight battle-tested technologies that there are certainly some pretty great IP-based alternatives to, but which replacing wholesale for some yet-another-IP-based-rebranded-messanger seems crazy. The beauty of SMS riding on the voice network is that it gives you redundancy. Phone doesn't have a data signal, but can get voice? SMS still works. Until we live in a world where GSM and friends are dead and everything everywhere is VoLTE, SMS still has a place as a fallback. I'm always a little surprised to come into HN comment threads about SMS and see so many people rallying for its replacement, yet we go into a thread about Slack and see many of the same arguments being made to defend IRC, etc.