I really like the idea of Nintendo trying to do something (even if it is barely effective) that promotes taking better care of yourself. They usually do it in a way that people find fun. Take the Pokewalker for instance, sure it's just a pedometer inside a tamagochi, but it rewards you for walking farther which helps lead to better health.
When I went to the doctor Thursday for a blood pressure check (which means it wasn't an actual appt. just that he wanted to see how the new meds he has me on is helping my blood pressure) he noticed it was still high and wrote me a prescription for WiiFit. Yeah, an actual prescription for a "game". He has a lot of booklets and pamphlets about it including one that has a $30 off coupon for it.
I know a lot of people will say that gaming has no room for stuff like this, but why not? People get pissed off when Roger Ebert takes a jab at it but then when the companies actually do something like this that helps it gain even a bit more mainstream credibility the same people still get pissed. It's not like Nintendo is saying you have to have this or you can't play Super Mario Galaxy 2 or Other M.
It's a good idea and if it helps people to be healthier or to be more aware of their health then it's a good thing in my opinion.