because it plugs into your TV so you can actually play games from your bed - I had so much fun playing Project Gotham racing is not funny. I had a PS2 but sold it recently (pretty crap compared to this) and now the X BOX has dropped in price I'll certainly get one.
It doesn't run windows, it runs a version of its kernel, that much is true - but vastly cut back. This results in more clock cycles for the game rather than for the OS - Hence bloody good game play on a 700 Mhz machine.