Most games do this though but you are right it does need to change. The worst offender was probably Wii Fit. Why the hell did they restrict the types and amount of exercise you were allowed to do. Baffling.
Nintendo is a video game company. They want people to play their entire product, and unlock stuff. Like a game. It's the same thought process used for SwapNote too, I'd wager.
Not saying it's right, but it could be an explanation.