The worst part is that for a DeFi loan, you need something like 200% to 300% collateral (look it up, it varies but is usually around that amount). This makes it less than useless for just about all reasons people now get loans. The whole point of a loan is that you're willing to pay extra over time in order to have access to more funds at the present. With DeFi loans, you pay extra over time and have less access to funds than you would have had without the loan.
It only really makes sense for crypto gamblers, who are hoping that their collateral has insane appreciation that will offset the downsides. If anything, DeFi loans are less like actual loans and more like crypto gambling partnerships where one partner takes a position with lower risks and rewards and the other takes a position of higher risks and rewards.