Is the Friedman rule being applied today?

In “The Optimum Quantity of Money and Other Essays”, published in 1969, Milton Friedman showed that the optimum interest rate is zero. The argument is that increasing money balances increases well-being (transactions are easier to make); the opportunity cost of holding money is the nominal interest rate; it is therefore optimal for it to be zero (for inflation to be the opposite of the real interest rate) so that the largest possible quantity of money is held. One might therefore celebrate the current low level of interest rates. A few questions remain: If inflation is negative, seigniorage (the inflation tax) is negative, which imposes the use of other distortionary taxes (Phelps’ 1973 argument); this argument has been put into perspective by others who have showed that inflation also creates distortions (for example Lucas in 1994; Chari, Christiano and Kehoe in 1996); How does this argument hold up to the fact that money is a component of portfolios (investment money) and not merely transaction money. It has to be assumed that the ability to hold a large share of one’s wealth in money and not bonds, because interest rates are zero, increases well-being. This is possible: money is liquid and risk-free. Ultimately, today we are merely seeing the implementation of Friedman’s old recommendation .