I think it’s more of a hedge against further devaluation. If the Euro goes to pot, Germany would want a currency of their own. Having gold on hand may give them the option to back a future currency.
I’ve heard this is the case for China as well. They are buying lots of gold to make the RNB more attractive in the world markets and to possibly replace the dollar as the world reserve currency.
But who knows what these bankers really want. They all work in the dark.