I've never understood the complaint. Once upon a time the central bank would load up trains and armoured trucks with hard currency that they would send to the bank. The bank would then loan that out for stuff (houses, cars, whatever).

The banks realised pretty early on that they could loan out more than they had in physical cash because people didn't need the currency they needed the bank cheque.

At the end of the day the banks would reconcile with one another and the central banks.

Now, because there's even less need for hard currency in our economies, the central banks can (effectively) email to banks how much that they can have to use for loans.

Accounting rules limit the banks on how much they can loan out.

Nothing has changed from when the hard currency was shipped around countries, except that it's done with a telephone.