the biggest risks of DeFi applications is,The smart contracts could be hacked.There could be a backdoor that allows someone to steal all of keys. What is the backup plan for this you have.Because we have to trust this and we need reason for that.
What happened is that you opened a DApp which hosts a smart contract and a pool of borrowers. So at the click, you decide what interest rate you want to give out a loan, if favouring, then lending is on the way. Concurrently, the smart contract automates lending and borrowing agreement.