Good point. I can only say that where I come from they are seen as something distinct, perhaps a category of food entirely their own.
There are also places in America, particularly the south, where macaroni cheese turns up on the vegetables list. I think that everyone kind of agrees that mac-n-cheese is a side, but not a vegetable.
And as far as I know contain a pretty decent amount of vitamin C at the very least.
Until you cook them? Vitamin C is not very heat resistant.
That's what I thought too until I actually looked into the matter, don't have source at hand but apparently 1 hour of cooking causes about a 30% drop in Vitamin C. Not that bad.
Do you know if leaving the skin on helps?
I was researching usage of pure vitamin C powder in cooked foods and tea. Don't think the skin matters much if the powder can survive.
They also contain a huge amount of potassium. Even more so than bananas.