A question that will become crucial: Confidence in the currency

The coronavirus crisis is going to give rise to very large and lasting fiscal deficits, first to respond to the crisis and then to kick-start the economy. For these fiscal deficits to not lead to a sharp rise in long-term interest rates, due to excess supply of public-sector bonds over demand (the level of savings is sufficient, but the share of government bonds in savings is too low), central banks must buy a large share of the government bonds issued and monetise them. The entire edifice of this support for the economy therefore rests on confidence in the currency , as economic agents must be willing to hold much more money and invest a growing share of their savings in money. If, given the abundant money creation, economic agents lose confidence in the currency , they will not be willing to hold the money issued by the central bank and fiscal deficit monetisation will become impossible. What indicators might there be of a potential loss of confidence in public currencies? Possibly the gold price and the price of cryptocurrencies.