I have a cell phone (not a smart phone) which I use about once a month. It has a texting capability which I would have to pay for, so I've never used it.
It is highly amusing to me to see people walk into a restaurant, sit down, pull out their smart phones, and fiddle with the thing while ignoring the other people at the table. My wife and I have seen that scenario many times.
Wouldn't it be better for people to converse and interact with each rather than stare at and fiddle with some electronic object while ignoring their dinner partners? Maybe it's a generational thing.
I think it all comes down to common sense and good manners.