The quick read; since 2001, Ecuador has used the U.S. dollar.
Why? Read on …
The sucre lost 67% of its foreign exchange value during 1999, then in one week nosedived 17%, ending at 25,000/US$1 on January 7, 2000. On January 9, President Jamil Mahuad announced that the US dollar would be adopted as Ecuador’s official currency.
Like about a dozen other small countries, Ecuador doesn’t have its own currency. It just uses the U.S. dollar. It went to full dollarization in 2000 after a financial crisis that saw its own former currency, the sucre, collapse so badly that people started putting their holdings into dollars, unofficially dollarizing the country’s economy. The government simply went ahead and made the switch official.
So there you have it! This is why Ecuador uses U.S. currency.