They are safeguarding what wealth they have. Look upon it as an investment if you want to. The physical movement of gold around the world tells you something is happening, some countries are just sucking it all up.
If we have an economic meltdown (let's hope we don't), paper money will be worthless.
Think of the hyperinflation some countries have known. Gold & silver always have a core value... paper money isn't really worth the paper it is printed on when the $hite hits the fan.