It's extremely useful in lots of situations but here is one example which might be quite common for people. You have a powerful gaming PC in your bedroom, and in your lounge you have a low power HTPC plugged in to your TV. It's a fully functioning PC, so you can browse the web on your TV, but the graphics card is a low energy fanless card, so no good for gaming. With this gadget you would be able to play even Crysis on your HTPC, without ruining it's silence/energy efficiency etc. As for the wireless issue, I don't think it's as bad as some people make out. I get a very good solid signal in my house, so I think it would work fine. And wireless is improving all the time too so it's daft for people to call this useless, especially seeing as it's probably a number of years from being available anyway.