Bitcoin is a cryptocurrency used as a means of payment to realize buy-sell operations between many people, but it is not an account unit because non-monetary assets are not currently valued based on it, but based on the other fiat money.
These means of payment are increasingly used by people, especially in countries where there is greater exchange control. This is because the instrument is not controlled by a central regulator (it has no counterparty risk), but this condition does not make it a financial asset with a stable price as is gold.
In the graph you can see the gold represented by the orange line and the bitcoin by the blue line. Many people could be attracted by high bitcoin growth. Making them think that it could be good to make money in the short term if they anticipate the trend of the moment (enter when it starts to rise and leave the position before it goes down), but not a reliable currency.
Bitcoin is not a good value store, this is because it has high rises and falls in prices (high volatility), nor is it a good means of exchange. That's why it has no universal acceptance (dollar and gold have greater liquidity today).
In addition, the value of bitcoin is only determined by the speculations in the supply and demand side, on what their future price will be based on historical information, does not have a non-monetary use value (no real utility). In contrast, gold has greatly increased its liquidity because goldmoney facilitated its use as a means of payment, it is a good instrument of savings due to its stable value and using the credit card provided by the intermediary company there is no need to go changing dollars, euros or other fiat currency to use.
For these reasons, I recommend using gold for saving instead of bitcoin, which may be useful for speculation by taking into account its volatility (its value can be increase to infinity but also decrease to 0). In contrast, to invest, I recommend equities with good fundamentals and long-term growth prospects.
Cryptocurrencies beat gold in popularity due to the lack of knowledge that a solid company like goldmoney increased gold liquidity by serving as an intermediary in the gold/currency exchange and having support of its deposits in real gold in banks with diverse locations worldwide. In turn, most people are unaware of the risk that digital money has: their prices can reach 0 at any time or simply decrease to a point below the purchase price and there is no rational basis for speculating their future prices only historical prices.