It seems like these pre-apocalypse wierdos were really fond of putting most of their foodstuffs in extremely bulky containers rather than simply dumping all of their flour, sugar, salt, spices, coffee beans, popcorn and so on into one big, easily sorted pile in a floor trunk.
What were they thinking?
Containers indeed do nothing for the food they contain, if that was what you were implying.
If you instead were wondering about uses for cardboard boxes and plastic bags than they can be used to make arrows and other crafts or as fuel for cooking.
The plastic bags can also be utilized in the vacuum packed food recipes.
Oh I use them for all kinds of stuff - as long as it doesn’t involve containing anything. 
I keep things in bags for roleplay’s sake, but boxes are too bulky for that and go straight in the trash.
Kinda feels like powders should have their own item category that’s treated almost exactly like liquids, except that they need to go in a box/bag and don’t care much about temperature.
Doesn’t seem like that would be a major implementation challenge. Not necessary by any means of course - but it always looks really weird when I dump a couple pounds of salt and sugar together in a storage space and can pull whichever one I want out without a problem.
Overall it seems like food in boxes/bags should have some kind of spoilage benefit - not as good as refrigeration, but still better that being stuffed in with a giant pile of miscellaneous viscera in your trunk. 
Food being contained inside boxes,bags,jars we’re talked about late last year but I can’t find the thread. I thought it was called “Floor Pasta” but I guess not. In any case, the idea was mentioned and considered but I don’t know if it went anywhere.
I know it’s not precisely what you’re asking, but aren’t plastic bags and cardboard boxes used in crafting arrows? That’s pretty useful.
I bring it up once a year or so just because its one of the more visibly silly things I encounter each time I play, as I carefully remove all my foodstuffs from their packaging and pour them into big piles.
f l o o r
p a s t a
spoooooky…
Dunno why you withdrew the comment when you’re 100% correct and I’m betting it’s on someone’s radar as a future feature.