Well, it's a potentially good idea. An immersive way for people to learn Expert tricks, or just cut out the bad parts of the game (say you bought a game, but it wasn't fun to you, just download a save, watch the game play itself out, take over for the final battle, voila. Done. Go trade it in for $$$).
Then, of course, it could be bad. Posted on YouTube, this could really spoil a ton of things, and result in a loss of sales.
We'll see.
EDIT: Oh, Wii Sports wouldn't have "sold" as many as it did if it weren't bundled with the Wii console. Yeah, SMB was bundled with the NES at times, but that game actually would have been bought, whereas Wii Sports would be nowhere if it weren't bundled with the console. Remember this when Wii Sports Resort comes around and doesn't sell.