I balk whenever someone calls DeFi 'a product'. You can't actually do anything with it. It's just a bunch of hand waving and shuffling more crypto around. The emperor has no clothes.
It's very normal in finance to call financial offerings, lending, loans, etc. products.
Some DeFi products offer nice rewards even - like somewhere around 12% pa for more risky, but about 6% pa for low risk products.
We are far from close to mainstream usage and early adopters probably will benefit the most.
If I go to a bank I can get a loan for a car and use the car I'm purchasing itself as collateral.
Right... so pure speculation then with no underlying utility.