Being able to save the world, princes or hostages, beating the living daylight out of my friends character or sniping them from far away, or skidding through the turns with 6000+ RPM, all without moving anything but my thumbs and index fingers is the real beauty of the consoles.
Screw having to know about the position of the 100+ keys on the keyboards and waiving the mouse. Screw the camera requiring me to turn up the light so it can see my hand-gestures. and screw the wii-type controllers flying through the air unless they are secured to my wrists.
If I want to break a sweat I go outside to work in the garden or do something on the house, I go skiing in the real world or play sports for real.
The sofa is comfortable for a reason, and it's not so you can get a workout while sitting on your ass.