The New Yorker is too clever for me

Like a lot of their humor, this New Yorker cover comes off as rather superficial. Or maybe I just don't get it. I assume the humorous implication is that the couple on the cover is ignoring the real thing right there in favor of the tiny screen, but that doesn't really make sense. They are there in the museum, after all, so they clearly appreciate the art. Is it the fact that they're taking a picture that's funny? Taking photos to remember a notable experience has been pretty common for a couple decades now, and it's not particularly amusing by itself. I guess it must be the digital camera. Really, though, what's supposed to make looking an digital camera's LCD display funnier or more worthy of wry artistic commentary than a traditional camera viewfinder would be? Is it uncool to check and see if you got a good picture? Is it classier to buy a postcard at the gift shop instead? What, exactly, is the point?