What are central banks – and governments – going to do about cryptocurrencies?  I was in New York last week to better understand what central bankers are thinking about   – and doing – with respect to “Digital Fiat Currency”.   The workshop was part of an ITU Focus Group Program on “Standardizing Digital Fiat Currency and its Applications”.  Central bankers, monetary policy and blockchain academics, NGO’s, and blockchain fanatics of all kinds were well represented.  Here’s what I learned: a lot of people are thinking hard about this, but we are still in very early stages.  Much is unclear, and there are serious debates on any number of issues.   I boil them down here into two fundamental questions:  what, and why?