Cause to the general consumer you get the best of what the PS3 can do (play HD Games) and the Wii (Causal /Physical type games) with Kinect, plus, a bunch of really easy to use apps for TV/Movies/Gaming/Sports/etc.. Its a fun package to play with kids and get the whole family to play - Kienct, then turn on a watch a cool movie, then, when the kids have gone, play some fancy HD games.
If you like your others systems, cool. But as I see it, its best package for all three.