This may be momentarily spurred by a recent post, but I would like to ask more generally why so many people use split (like bento-style) containers for meal prep?

I’ve been doing meal prep since I first learnt how to cook, it was just how we always did things, and I’ve never seen any reason why it would be beneficial not to use a normal single container to hold the food? Even if it’s stuff that shouldn’t touch in storage, you’d want to have them in fully separate containers so that one can be tipped into the other, to combine to eat? Or to microwave half but not the other?

That also leads me to my confusion about metal boxes with food that would ideally be heated to eat. How do you reheat a curry in a metal box? I definitely get that plastic isn’t ideal, but I use glass for all my meal prep and it works a treat, as well as can be used in the microwave and the oven if I want to.

All the other ways of doing things confuse me immensely, but that’s why I’m asking. What is the purpose? What is the gain? What am I missing out on?