22, the monetary system is already as good as digital. Something like 95% is recorded in digital ledgers while just 5% is in notes.
If I should worry about a future total digital system [I use the term blockchain loosely it might some iteration of that] then I should be worried today - I'm not.
Besides, the argument as I recall is that money supply [in whatever form it takes digital /notes ] should be backed by something tangible such as gold. And that the world is sinking in a pile of debt. I argue that putting in constraints would restrict growth and put growth into reverse creating a dark period indefinitely. It won't happen so don't worry. The current system will evolve in line with technology not go back to a previous century. Gold will still look good on pretty ladies though.