Great post, Gary. I like that you've touched on something that most people have such a polarizing view on.
Personally, I don’t have an issue with people using their smartphones when in the presence of other people (I do it daily) but I DO think there becomes an issue when people become addicted to the superficial relationships / interactions in their phones and miss out on the real, deep relationships that are in front of them.
For example: a parent ignoring their child to incessantly check the number of likes they got on Instagram. They are getting an ego boost (or whatever other psychological reaction is happening for them) when they see the likes roll in and that comes at the expense of the moment they could have shared with their child.
So, I think there’s something to be said here about awareness of the situation. Being aware of your situation and choosing when it feels appropriate to do a phone check or when you should set it down and dive in with the person in front of you is key.