Nope, they can't be redeemed at the cage. They're used for various things. One example is in pøker tournaments. You might buy in for $20 and be given $500 in NCV chips to play with. You can't just quit and cash the chips in, you have to play and "win" the tournament to receive anything. They are sometimes also used for promotions where you can bet them and keep your winnings (if any). Probably other uses that someone else can think of.