If anyone still needs this, here's my answer from Edge2020:
A traveler who plans to spend several thousand dollars as they travel over a period of two months may experience a shortage, or lack, of a country's currency due to constant fluctuation of the currency exchange rates. If the rates go up, the individual may not be able to afford major travel expenses like meals and lodging. It may limit their ability, also, to pay admission fees for tourist attractions or purchase souvenirs as a memory of their trip.