> Because that's literally the only way banks make money. Cars, houses, whatever -banks are after the interest money.
Lending for bad investments isn't a way to make money. It can work for the banks if they resell the loan, but in that case one thing they definitely aren't after is the interest money on the loan they no longer hold.
> The loan is a fake number that gets transferred from your account (as debt) to theirs, as digital numbers too, all under the "trust" that you can withdraw all of it one day. The real money in this is the interest that the bank will take. This is why if all people decided to withdraw all their money, banks would refuse, aka a bank run.
The reason banks "refuse" to redeem all of their deposits at once isn't that this would stop them from earning interest on their loans. (This sounds like nonsense, but I don't see another way to interpret your sentences...?) It's that they can't, because they are never holding enough money to cover all deposits at once.
> The loan is a fake number that gets transferred from your account (as debt) to theirs, as digital numbers too, all under the "trust" that you can withdraw all of it one day.
Also, this sounds like you're describing a loan from the customer to the bank. A deposit can indeed be modeled that way, but in context you appear to be talking about loans from the bank to the customer. Can you clarify this?