I meant to talk Swift in the last post

 I digressed.

Central banks have Swift, a huge competitive platform.  So imagine we combine Swift with secure personal ID. In this model, the hierarchical ledger system beats anything else, there is smooth intermediation between account ledgers and cash in hand. Regional banks can release bearer cash and it show up mostly regional, then nearest neighbor. The transaction history gets remembered, risk reduced in the hierarchical system.

So, having a mini Swift bank in your hand is probably the best opportunity for the central bank to whomp the market. By far, the simplest, most flexible approach. If the Fed wants to do this right, go talk to the logicians who know about contract reduction, they will agree wit me.  There is a great opportunity for productivity across the board. Secure personal ID makes this all happen.