I am not arguing that expiring currency is unprecedented. Further, I am aware governments have had control over the money supply for thousands of years.

Main thing that worries me is the sophistication of the control. What I do not want is all economical activity to be corralled into a financial system where states/bankers can see every transaction, take your assets at a key press, and destroy your savings.

State backed currencies seem like a good idea, so do legal alternatives and anonymous payment options like physical cash.