Cooked Content -- Use and Storage

I’ve just noticed that the cooked content folder (Saved > Cooked > Windows > MyProject > Content) requires alot of storage (50% of the Game > Content folder).

I’ve never used this content. AFAIK, I’ve only used assets from the Game > Content folder.

Can someone please explain the use of this ‘cooked’ content?

I’m trying to optimize my project’s storage requirements, so any advice on that topic would be helpful as well.