So, the thing about BTC and its price fluctuations is that they are determined solely by how much BTC is being sold and bought within a given point in time. The value of the fiat being used, arguably, has little or no influence over it. The thing about gold is that much of it is tainted with other metals nowadays, so it is more or less useless. Let's not forget about the fixed supply of BTC. That alone dictates the direction of BTC.