As far as I know the strength of one currency lies and is very influential on the country's own economy, for example Dinar Kuwait (KWD) as you say, it is true but their currency is strong because it lies in their economic stability over The basis of oil exports, but if their oil reserves run out certainly dominating the Kuwait economy can collapse, it has happened to Venezuelan.

The situation can also occur in other currencies such as OMR, BHD, Jod and so on, in contrast to the dollar, for me in terms of the global economy the strongest currency today is the dollar, even though it is exchanged in a distance from the currency KWD and others, are not easy to shake, for example such as the formation of BRICS, but the strongest dollars are globally.