Having a spread between cost of borrowing and net return is how banks make money. Pay deposits X% while earning Y% on said deposits, where Y > X. Another way to make money is to buy collateral earning Y% and apply a structure on top of it and sell the product as yielding X% and pocket the difference, where Y > X. All structured products (e.g. MBS, CLOs, ABS, CDOs, etc) essentially work like this.

They wouldn't necessarily need to borrow money to do that. The naive play was using something like TERRA to earn 20% and pass through 8% to the depositors. But the spread amount itself should have raised eyebrows. If someone is paying you 20%, you're taking some kind of risk. And the worst kind of risk is risk you don't understand

I guess if you believe in Web3.0 the best place to park your money is ad agencies

The same was said about MoviePass