Many of the barriers to trade exist not because of a lack of markets or customers, but because there are major barriers to getting products to market at competitive prices. Transaction costs are significant for companies ─ not only the straight exchange costs, but also the cost of converting, paying, and hedging funds just to pay for the goods and services. Having a common currency means that many of those transaction costs disappear and the savings can be reinvested back into firms' productivity and innovation. Basically, useless costs turn into productive costs ─ with longer-term benefits to the whole economy. By unifying some of the currencies, whole economies benefit and grow more than they would as independents. So a common currency provides for a strong economic foundation that all can benefit from.