The interesting debate raised by the Friedman rule

The Friedman rule says that the optimal interest rate on bonds is zero, because it is optimal to eliminate the opportunity cost of holding money. An alysing the Friedman rule raises a few very interesting questions: First, should monetary policy abandon any countercyclical role and be set according to a structural optimality, as is the case with the Friedman rule? Second, in modern economies (where there are new payment methods), does holding money always increase the well-being of households and companies? Third, are the distortions related to inflation more or less important than those related to taxes (other than the inflation tax)?