(1) Collateral types available: Suppose you hold BTC and ETH in your account and want to borrow USDT. With single-collateral loans, you can only pledge either BTC or ETH to borrow. With multi-collateral loans, you can pledge both BTC and ETH to borrow. (2) Ways to manage collateral: With single-collateral loans, a new order is created each time you borrow. With multi-collateral loans, your loan and collateral amount (calculated in USD) will be added to your previous loans. In other words, you can use the collateral of your existing loans to secure a new one. Suppose you pledge BTC and ETH worth $1 million altogether, but only borrow USDT worth $500,000. When you want to borrow another $100,000 USDT, you don't need to add any collateral since your existing collateral is of high enough value to cover your new loan.