Gold is just a piece of metal, mostly like any other metal, but scarcer.
The scarcity and the shinyness gives it's value, which is lame.
Bitcoin has real high-tech network behind it, and a cutting edge technology for 21 century financing.
Gold is just a bronze age primitive metal.
It has the faith of an awful lot of people. That's all that counts. If everyone believed used sanitary towels had magical qualities they'd be hoarding them instead.
I think gold is crap. Enough people disagree to make my opinion irrelevant.