Inflation is a tax on nominal wealth, so if asked individually about whether that tax should be positive or zero – or even negative, thus becoming a subsidy – agents in the economy would tend to choose the lowest possible tax.
But assuming that the economy faces various frictions, and that those frictions interact with zero or negative inflation in ways that might be costly for the economy as a whole, theory argues that a “benign optimizer” would not necessarily opt for a zero or negative inflation tax.