The food booth items are snack credits. This makes things like the filet from Canada a great use of a snack credit.
You can convert a quick service to three snack credits at one booth (so if there’s three things you want from one place, it may make sense depending on your other plans over the trip). Alcoholic drinks do not count as snack credits, however, so you’d be sacrificing your “alcohol entitlement” that comes with a quick service credit by doing so.
It can still be a great choice to have the dining plan during festivals. We had free dining during food and wine last year. There were three of us there for nearly two weeks. We used most of our snack credits at the booths and we still ended up converting a couple quick service credits to things like getting a lobster roll a piece when we didn’t feel like sharing. This was before alcoholic drinks were included, though, so the theoretical value of a quick service credit is a bit higher now.