Defi Advantages?

Hi everyone, big believer in the tech, but I was wondering.. I understand all the technical benefits behind defi like transparency, however more fundamentally it seems that for defi to enable trust, the borrower needs to deposit more than they’re borrowing to access the loan.

How does this even make sense, if I want to borrow money from the bank I’ll get it with $0 down bc I’m socially identifiable/legally obligated to repay the loan.

With a smart contract, the collateral is just more money. Why would I even be borrowing less money with more money to begin with?

Makes more sense with NFTs (that could represent physical assets), but what about cases like DAI? Obviously there’s a reason.. since defi is successful so far. What am I missing?

Thanks v much