What is the Storage mechanic?
Storage is your $cOIL storage. It is represented by the amount of $cOIL you hold in your wallet.
From Storage management you can choose the exact amount of $cOIL you want to refine.
Storage is also useful if you want to compound your rewards. Store your $cOIL allow you to buy more items, Reward Items or Booster Items without to have to pay refinement fee's or wait for the refinement to end.