Instant communication, any minute, any time. Connected with as many people as you want to be, all at once, yet no one needs to know who all else you are talking to at the same time. And the feeling that you're someone, because there is always someone texting you or whom you can text. I don't know if that's the whole fascination, but it is part of it for some people at least. Younger people I don't know about. Older people who get caught up in it... well, what if your boss called you in to talk to you and then, while you sat waiting for him, he sat across the desk and texted and laughed to himself or his secretary about incoming messages, then looked up dazed and said, "oh, uh, yes?" as though he forgot he had called you in? It happens. It'ss very rude, when that happens, to say the least. Unprofessional... well, won't go there.
Why text in church?
(And please don't text and drive.)