With intertemporal smoothing of returns, good investment years subsidize bad investment periods, with a  18  The very hypothesis of ergodicity of most economic and financial time series has been questioned from time to time (se, for example, Davidson, 1991) and becomes hard to believe in crisis periods.
At the ECB we now have an instant payments system known as TIPS which is inexpensive and works extremely well. We need to learn to link these systems with our colleagues in other countries to facilitate cross-border payments. Innovation is also an incentive, a stimulus that enables us to work more effectively. Currencies are normally minted by states.