The first computer I ever owned was a PCjr. Total P.O.S. But it had a wireless (Infared) Keyboad and I liked it. It had to be line of site, which was limiting, but it was cool to sit on my bed and play King's Quest (too far for a cord). Of course it didn't have a mouse, so
I can't speak to that.
I use a Kensington Trackball, so it doesn't move, but when I am forced to use a mouse, I am enough of a spaz that the cord gets in the way, so I can see a cordless mouse as being truly useful.
There is also the issue of asthetics. The iMac would be even more attractive without the cables.
However, I would say the appeal is mostly for the coolness factor- I don't think laziness has anything to do with it. Charging devices and changing batteries take a lot more work than plugging something in once.