OP gold and other metals are their own market. Bitcoin and other cryptocurrencies are also their own market.
The thing is though that if Bitcoin eventually fulfills the objective of Gold - a stable store of value - then why would someone buy Gold?
People buy Gold, not because it is shiny, but because it holds its value compared to fiat, which has inflation.
If Bitcoin can offer this at a superior level to Gold (when Bitcoin eventaully has a higher Stock to Flow Ratio) then people will likely start opting for Bitcoin instead.