At the highest level, governments will be the hardest hit, as they will no longer be in control of the new currency as they did with paper money. The idea of "printing money" has consistently appeared as a proposal to tackle financial instability, but this option will disappear as e-money must be "exploited" to come.
In general, converting from paper money to electronic money is a completely realistic scenario, and it will also change the face of how our society spends and saves.