Yup we did that with our magic bands last year. Just make sure you keep an eye on what your spending as it's very easy to get carried away and the resorts do have limits on how much you can charge back.
I bought a gift card at Epcot that came on a wrist band - think I put $50 on it. Another idea if you are worried about getting carried away with charging back to the room.
We did that last year it helped to stop the over spending I was taking about. That way you still have cash but it's limited to what you put on the card. They work as normal gift cards as well not just on the food booths so if you have left over money it won't be wasted.
We bought one of the F&WF gift cards on the wrist band last year too (and did the same thing for the Flower & Garden Festival this March). It is a good way of limiting your spending on the snacks and you can buy the gift card and charge that to your room, so still no need for cash.