> When you "transfer money" from your bank account to another, your bank has to physically move the associated cash from it's vault to the other banks vault, by hiring secure trucks, people, and so on.

That hasn't been true for, uh, centuries. It's like literally the entire point of banking, to allow financial transactions to take place without having to physically haul around collateral anywhere.

(And if you want a digital version of what banks actually do, it's called SWIFT, and has been around since checks Wikipedia 1973).