This is the food that's chosen to stay behind. The food that'll keep you fed some other day. And if, Heaven forbid, you leave it alone… well, it'll make a life of it's own. Which you won't smell, thanks to the tight seal on these dishes.
Without leftover storage, you'd have to eat new things every day. That sounds good, until you think about how many different foods are MORE delicious on the second day. Face it, without storage, you'd miss out on many great flavors.