I have a “dumb” phone. (LG Cosmos- NOT touch, with texting). I got it because I commute over an hour every day, and my mom wonders why, because 95% of the time it’s sitting at the bottom of my bag, dead. (Baruch dayan emes.)
I think it depends in whose hands you put the phone. I have friends with smartphones who SnapChat and Instagram EVERYTHING (it gets extraordinarily annoying), and I have friends who do pretty much the same things with their phones that I do with my computer. It all depends on the person and his/her strengths- there are no absolutes. But I can see Shraga’s rationale.
GAW: Isn’t it possible that it’s more of a minhag hamakom type thing? If I lived in a place where nobody used a smartphone for ideological reasons, I probably wouldn’t use one for the same reason that I’d wear different clothing in Meah Shearim than at home.