With a multiplicity of currencies there are always extra costs and additional barriers to cross border trading. There is also a lack of transparency in pricing. In the new order it will be possible to compare prices directly from one country to another and this should be of considerable benefit to the consumer.
A single currency will also lead to broader and deeper financial markets in Europe, thus increasing the choice of financial products for businesses and consumers. Europe also needs a single currency if it is to be a leader on the international stage.