The majority of the activities in Wii Fit are not games but exercise and fitness activities. There are some games in it.
The reason why DDR is not a video game and it is a game is because you are dancing and the game itself is just a visualization of what you are doing and not actually the main experience.
Wii Sports is not a traditional video game because it has the players engaging in activities mimicing sports and not inputting commands into a game. Meaning this is a sports simulation game but not a traditional video game.
I never said DDR is not a game, it's just not a video game. Wii Sports is a video game just not a traditional one, but rather an activity simulator through motions, but in the case of Wii Sports the activity alone without the game would be pointless because it isn't actual tennis or golf or whatnot.
On the other hand in DDR you can dance and do steps without having the game in front of you and it would still be the same experience except you need to software for a visual representation and for score tracking to be easy.
Same way that Singstar is not a video game, it's a karaoke game. You are singing, the music and score and visuals and whatnot in the game are not the point of the activity, those are just tools in the same way that having a recording while singing is a tool.
Thanks to Blacksaber for the sig!
