Suppliers can deposit their assets to Parallel Finance. For providing liquidity, in return, they will receive some of the borrower's interests.
Suppliers can also choose to collateralize their assets for borrowing other currencies. This is useful when the price of a certain currency fluctuates significantly and you want to borrow another currency for hedging. This also solves the liquidity of your cryptocurrency.
Currencies have different Collateral Rate which reflects the stability of their price. The more stable the currency's price, the higher the collateral rate. Stable coins USDT will have a higher Collateral Rate.