We used a snack credit there last June. You can't use it on their signature sundaes but I got a scoop of ice cream with hot fudge sauce. As long as it's under $6 or $6.50 ( I can't remember which) you can use a snack credit.
However, it seems that they did not contract for this year. So it might be a definite no. If you are staying onsite, you could always charge it to your room and use your gift card to pay off the charge.