I'm a gamer. Brought Wii Fit. Good exercise; helps with balance and core. Very good for tennis training.
I know many non-gamers. I was stunned at how many purchased or received a Wii and Wii Fit (or just Wii Fit) over the holidays. A funny thing happened with them. They brought a few real games like Boom Blox and Mario Kart Wii. At the moment, you might think nothing of this. Consider the implications to gaming: a wider demographic means developers might consider new ideas given this different demographic (in addition to stagnant ideas like... Halo 3). It also means that in the future, you might get some bright minds into the gaming industry who otherwise would have never considered it. The gaming industry is in dire need of the sort of people who didn't grow up gaming (no offense, I am one of these people, but development and gaming in general are stagnating in the vast majority of the industry, due to narrower and narrower catering to the hardcore and industry regulars who have this gaming background).
In the end, Wii Fit is good for gaming whether you like it or not.
Vocalizing distaste for it simply indicates that your mind is, or belongs back in middle school.