The demo thing is dumb. It's not just the 3DS thing. It was dumb when the Dead Space 2 demos were removed from PSN/XBL. Now if there was a way to see if adding restrictions would make companies more comfortable with releasing demos, maybe there'd be value to it. As it is, it's like, why would you defend a move that works against the consumer? It's dumb.
also, I know PS3 can add time restrictions. With play and time restrictions, it would be nice if you could rent downloadable games. Don't the xbox and ps3 movie stores do that? you can rent or buy the movies.