Containers

[Uma]

Is there a benefit (aside from getting rid of screens full of different objects) to building containers like barrels?

[sanchez]

Containers such as barrels as well as portable storage like amphora and duffels hold 'raw' materials only, i.e. things measured in grams. They do not hold objects. Storing things in containers instead of on the ground will prevent rot. If you leave for example a pile of meat on the ground long enough it would otherwise disappear. Storing food in containers in your invesntory will prevent you from eating it automatically, which can be helpful if you have the eating sickness.

[ceselb]

Yes, there can be a benefit. Some places give out free food and keeps a storage item stocked at all times. This prevents rotting while still keeping it accessible for all.
For general storage they're not so good though, much cheaper to build a shack or something.