I think his implication was that silly like this shouldn't be a phenomenon.
I'm not just "hating." People already look at their smartphones enough, especially in situations where it's rude to do such (dinner; meetings; conversations; crowded places, etc), so this "game" will just further worsen that problem. Yeah, I need some dip pointing his phone at me while he looks for Beelzebub.
"Well, it's getting fat kids to play outside."
And what they're doing is something totally passive that doesn't teach any kind of skill, present a real challenge, or really improve overall fitness (muscle strength, hand-eye coordination, body control, etc) like, you know, sports.
Maybe you like the idea of kids spending hours outside strolling around looking for digital creatures instead of playing basketball, soccer, football, baseball, frisbee, whatever etc, but I don't.
The game would be more interesting and "healthier" if it incorporated challenges that require a kid to make ten baskets, dribble a soccer ball for 500 feet, etc.