Would be very useful/worth it = for those who have unlimited Bandwidth ISPs.
But another good use for this is just using it for game demos. Provided you don't have to pay a fee per month to access the service even though you don't buy anything.
Instant Demos, yes please.
Brb, getting netbook.
EDIT: This: http://www.streammygame.com/smg/index.php
Also, this could be done with VNC to a computer at home trough a computer elsewhere, but then again you would depend on a good broadband connection between the two.