Devices like the Punkt MP would great in an ideal world (if they had support for something like XMPP). But in practice, a huge amount of people use Telegram, or WeChat or some other network for which you need a native phone app.
In practice, that's me as well; while here in the US texting is big, in years abroad I don't think I had a single conversation via SMS - everything was in apps.
That makes phones like the Punkt an ideal more than something practical. But I still want one. It appeals to the minimalist in me, big time.