Correct, I do mention that often and not a single goldbug has refuted it.
It's a bit like buying a vintage car and hoping that you've bought the right model, the right year, the right colour, the right condition and all other manner of imponderables that you dream is gonna tempt the next sucker, but at least with a vintage car, it might be fun.
As for your mention of AUD or USD etc., people actually need them, it's the way business is done, I've just traded some USD for euros myself, I didn't buy any gold because if I went into the local supermarket with it all kinds of rumours would be spreading about my unusual behaviour.
Smooth talkers have made goldbugs out of many normally sensible, well balanced people, something that will inevitably result in a financial undoing for many of them.
