The Bank of Japan is leery about cryptocurrency, specifically central banks issuing one that could lead to damage to the economy. Leaving aside the damage these banks did using fiat, one of the major "problems" is that member banks won't be able to borrow, in turn not being able to lend. Central banks all over the world are looking into cryptocurrency especially in the wake of Facebook's announcement of bringing out one themselves through a foundation it set up.
Source of shared Link