This is a game that got savage reviews on gamespot and ign but in all honesty I think the guys reviewing this title completely missed the point of it!
It is a title aimed at young girls. It is a collection of funky songs with fun and funky choreographed dance routines with some loose wii interactivity providing some "scoring". This title is about presenting a fun and funky easily accessible prepackaged set of music and dance choreography for girls to have fun with!
I know my girlfriends 3 and 6 year old girls had an absolute ball with this one. And mind you my girlfriend was saying what fun it would be to pull this out to play with at our next party! So I am pretty sure in that context it would also appeal to "older" girls too
As a side note, a lot of fitness titles include a dance section in their aerobic workout offerings. Most of these are really cheesy, boring and stupid. If you want to break up your workouts with some dance then I recommend this as a much better alternative.