It all depends on how savvy you are with them. There was someone on the boards talking about how you can use them as dollar values instead of using them as separate checks i.e. Snack check. Premium Character check. If you use the cash value you can get closer to the amount of money you are using your total. Maybe paying a few cents over instead or giving them a dollar or so in change you don't get back.

It doesn't save you money. But some people would use it as away to save the money for food ahead of time by adding it to the vacation package through Disney Travel Co and making payments. So I suppose it would depend on what you are looking in to it for.