Yes, it looks cool and is a sight to see at nights.
On the other hand it's sort of saying "We're all techies who can't put away our phones at a football game, and here's proof."
It's a lot like the cigarette lighters at old rock concerts from which it takes its cue. They were a sight to behold, but the underlying message was always "Hey, we're all stoners and junkies and we're proud of it."
That's a little bit harsh perhaps, and like I said, I do think it looks good. I think I would like to see it voluntarily limited to in between the third and fourth quarters, if it were up to me. Use it as a cue to signal the fourth quarter, and then but the phones back away and start cheering loud again.