Gold holds it's purchasing power relative to the currency you...

Gold holds it's purchasing power relative to the currency you are valuing it in when that currency is being debased. This means you can convert it for more currency (purchasing power) in the future than leaving your dollars in the bank or wherever to earn interest.

Gold is itself a currency just like paper. The difference is that it is difficult to debase because it is relatively scarce, so when paper is debased it rises as a store of value. Paper is not scarce. It is zeroes in a computer or paper in a press. If i found a giant new gold discovery in the middle of Aus, where there was 200 trillion tonnes of gold nuggets on the surface it wouldn't be worth sh*t either.

In effect it is a hedge against govts. intent on devaluing the currency. Can't eat gold?? Well you can't eat paper either.

Gold will fall when bankers stop prinitng money and confidence is restored in govts. and economies. At that time it's likely you will get runaway inflation and interest rates going to the moon (think Volcker era) is what will kill the gold price as paper currency becomes attractive again because bankers aren't printing it and you can get 10-15% interest on deposit.