I'm not a PT or anything, but my impression is that BMI works OK if you're a female of average built and height. The more you differ from that in muscle, height or gender the worse BMI works.
If I got to my "target weight" according to the BMI standard, I would look like a skeleton.
But BMI was probably the obvious choice for Nintendo. What would be better, get out your measuring tape? That's not "cool" enough.
Edit: Oh, and I'm eating chocolate right now.







