Nintendo 3DS producer Hideki Konno spoke with Wired about upcoming 3DS features, particularly 3DS game demos that he thought was "technically feasible" but questionable as to whether they're worth Nintendo's time:
I question whether or not demos are effective. There are cases where people play a demo game and they're satisfied with that play experience and they don't buy the game.
There are also times when they play a demo and think, 'Wow, this is great, I'm going to buy this when I have the chance'. So whether or not it's an effective use of resources, I'm not sure.
My solution? Put out demos for good games. (That way, we'll know which ones are
bad not yet ready to be good.)