I've intentionally never owned a smartphone myself. Our kids don't have it either. It is always fun to suddenly notice during train trips that we're more or less the only family here occupied with actual, real-life talking that also involves actual eye contact, lol.
That being said, maybe the communication pattern of two smartphone users sitting side by side is nonetheless still signaling the same humanly care, warmth, etc. Yes, there is a (IMO silly) technical device in between, but I'm not sure if all this would actually mean that it is "less humane" etc. It's just... different. Maybe.