I asked for an insight to the situation in North Korea. @MIROW says this.
"There are no ATMs and while they had planned to introduce a national debit card scheme the international card schemes like MasterCard and Visa do not operate there due to US trade embargos.
As for hard currency banknotes, US$, EUR, and Chinese RMB can all be used interchangeably in North Korea.
I would recommend using Chinese RMB for smaller purchases like water, snacks, souvenirs. EUR are good for entrance fees to special events. US$ can be used everywhere else, and much like in other countries in the world, it is the currency of choice.
It is best to bring a mix of these currencies and to bring smaller denomination notes, as some vendors will not have the right amount of change.
In addition, I have been told that North Korean banks do not take notes that are worn or torn, issued prior to 2000 or generally look like they’ve been “washed.” Try to bring newer, cleaner notes.
There are no ATMs or bureaux de change offices/kiosks in North Korea, so be prepared and obtain currency before entering the country from China or South Korea."