About USD and AED
US Dollar (USD)
The US dollar is divided into 100 cents and is used in the United States and several other economies, and many tourist businesses elsewhere quote prices in dollars. When a card terminal in another country offers to charge you in dollars, that is usually a dynamic currency conversion with a poor rate; choose the local currency instead.
United Arab Emirates Dirham (AED)
The UAE dirham is divided into 100 fils and has been pegged to the US dollar at about 3.6725 dirhams per dollar for many years, so the USD-AED rate barely moves. Cards are accepted widely, and taxis and ride services also take cards.
Exchanging USD for AED
The rate above is the mid-market rate for USD to AED. Banks, card networks and exchange desks usually apply a margin or a fee, so compare the amount you would actually receive. If a terminal offers to charge you in USD instead of AED, decline: that conversion normally uses a worse rate.