The food trucks didn't offer anything appealing for snack credits. They seem geared towards maximizing QS credits.
In Disney Springs, my kids used their snack credits for ice cream at Ghiradelli (it was ginormous for a snack credit) and a smoothie.
We tried to find interesting options for my "clean eating" DH in Disney Springs but there was pretty much nothing. He used his snack credits mostly in Epcot and for breakfast in the Pop food court. The various parks had much more interesting options. In Disney Springs, it was mostly desserts and drinks.
I don't know if I would recommend paying OOP for the ice cream pail at the waterpark, Its fun, but with the vast amount of snack credits you have, you can buy individual ice cream sundaes and that would be of more value. That said, I get it. I have paid OOP for the kitchen sink and it was a blast