We used many of our SC last Oct on bites at the F&WF. The only food item that wasn't allowed as a SC was the Ice Cream with Grand Marnier on it at the Dessert booth. I'm assuming because it was alcoholic.
We had the QSDP so we had 2 SC each last year. It gave us a lot of SC to use. Now you only have 1 SC per person so if you want to maximize your SC usage there are some items you might want to pay OOP for. There were some items as cheap as $1.50 (also at the Dessert Booth)
I have a QSDP dining report with many photos of the food we ate at the F&WF last year. Click on link in siggy if you want to check it out.