The dollar is king in weak lands like Russia and Argentina.

On CNN today saw a story people in Moscow demonstrating,that they can't afford their mortgages because denominated in foreign currencies.Obviously the Russian Banks knew the Ruble would be worthless so they wanted to be pay back in currency that was worth something,henceforth,mortgages in foreign currency like the dollar.
Watching Bloomberg T.V the Latin America gal said,big deal in Argentina are done dollars not pesos
because the Argentine peso is worthless.
Funny not long ago,there was much talk about replacing the U.S Dollar as international reserve currency. Of course, in early 1970's during the oil embargo it was said the Arabs would overtake tthe U.S as world economic power,then in late 1970's it was Japan to rule the world,of course,Japan has been in recession the last twenty years,now China the smart people say will rule the roost.But somehow the U.S always seems to come out on top I think because we know the smart people ain't that smart.