I have been using grape leaves as a green vegetable. I don't have muscadines, but I'm pretty sure they'd work as well as vinifera or labrusca, both of which work.
Often they're pickled, so they keep into the winter.
https://ferment.works/blog/fermentista-lacto-fermented-pickled-grape-leaves
They also make a good "lid" for other ferments so the little corners of the veg don't stick up out of the brine.
Obviously you won't need many for stuffed grape leaves, though the round form is probably easier to stuff than european grape leaves.
If you chop them fine and stew them for a while they make a nice tart addition to mixed greens or to a soup or stew.
I also use my grape canes for basketry and kindling. Probably work great in a rocket mass heater.