Global trade growth has been in a slowdown for a decade. Contributing to the trend is a recent rise in protectionist policies, particularly in the United States. On top of it, Brexit, no matter in what form it takes, is projected to decrease trade volumes.
Some people claim that the main reason why gold became money was that women liked it. Others claim that it is the faith that makes us use a certain good as money. By that logic, even water could become money just by virtue of us having faith in it.