In Cambodia the official currency of the country is the Real – but I never once exchanged USD for Real and I only received change from purchases in Real a handful of time. Each time, the person handing me the change apologized for not having enough USD to give back. USD is unofficially/ officially the main currency used. All ATM’s dispense USD. In perfectly crisp and unblemished bills. In Cambodia, if your money is tor, ripped, or even creased in the corner, they will not accept it. I learned this right away at the border when I handed over a $50 and it had been folded in half and denied. I don’t know many people who keep their money completely straight/unfolded/unbent. It was refreshing to have currency that I am familiar with for a few days – and not having to do math to calculate the exchange rate for everything I ate, drank, or purchased.