Delegation to other contracts. For instance I need info about price of some particular pair. I deployed another oracle contract that would look at uniswap ratio and return the price. I put in the oracles address in my main contract. Now if I want to add another exchange in my calculations, I would deploy another contract with the same interface and replace the address in my main contract. To keep the main contract decentralised, the decision of changing the oracle address var should be taken by DAO