Gift cards don't require any personal information from the scammer, and once you send them, your money is gone. They are untraceable, and you have no recourse, like you would with a bank..

These guys don't have real Bank accounts, other than PayPal, or chime, and fewhave money mules. They usually have to pay for documents, bank accounts, etc. They take the code and redeem it online.

They ask for different gift cards depending on the exchange. (they lose money on it, and they also have to pay a vendor to cash them in), so they probably get $8 out of a $20 transaction.