Still the fact is that it is inconsiderate, or plain rude, to be "somewhere else" when you are sitting with other people who all took the time to physically be with each other. If a few people get together and spend large amounts of their time on their phones, then why get together at all?
>After five days without phones or tablets, these campers were able to read facial emotions and correctly identify the emotions of actors in videotaped scenes significantly better than a control group.
The OP places greater value on face-to-face conversation. I'm saying that the OP takes this too far, that electronic interactions should not be dismissed so readily.
You may have huge brain and trillions of times of the computing capacity of a simple calculator, but it's still going to beat you at arithmetic. Know your limitations and embrace your strengths. You're not some general purpose machine; what's the point in pretending otherwise?
Why do you care how other people enjoy themselves?