What makes the market cap for gold a good estimate for bitcoin? I would like to know the price of bitcoin where the dollar cost of a transaction was roughly in

What makes the market cap for gold a good estimate for bitcoin? I would like to know the price of bitcoin where the dollar cost of a transaction was roughly inline with a credit card transaction. Another systemic risk: government regulation and/or shutting down exchanges to combat money laundering and tax evasion. Good luck insuring against that.