If you will be needing cash normally you would liquidate your cryptocurrency investments

Unless you are a holder of BitShares. Then you can use your BTS as collateral to borrow bitUSD which can be converted to cash with relative ease. As long as you maintain a sufficient collateral ratio to avoid being margin called or force settled, you never actually let go of your BTS in the process (you even retain their voting rights), as they stay locked in a smart contract on the blockchain (no counterparty risk) until you close the debt position.