It's not that interesting of an app, just screenshots from the Wii or 3DS games, screens from pre-rendered videos from the games or trailers and adverts, or just character artwork.
It'd have been better if you received a new card now and then but you have to spend playcoins to get new ones. Not even new ones at random or anything, you can buy the specific ones you want.
It rides too heavily on the assumption you're gonna encounter other people trying this out. I'll save my playcoins for where they're needed, Streetpass Mii Plaza.