How do we measure wealth? In some unit of account. Money is meant to function, among other things, as a unit of account, the denominator for any given asset value. But if the purchasing power of a currency is unstable, either due to inflation or deflation, this distorts the way in which real wealth is measured. For example, if your benchmark unit of account is the Zimbabwe dollar, you have made outrageous profits during the past few years almost regardless of your choice of investment.