Gold is another store of value, but not that unstable. It reached 2000$ recently and was above 1000$ for many years. Those who invested in gold back in 1900 would have made a great choice since it costed only 20$ back then if I'm not wrong. (Although dollar was way more strong than now)
Bitcoin can lose 500$ within one night. Gold can't. Why that?
Bitcoin is decentralized and can not be constrained by anybody. Where gold is utilizing from thousand of years and the government itself uphold it.
If the price of bitcoin falls $500 at nights then remember it can be increase double at nights.
Bitcoin was made in 2008 and now the following years, its cost is triple.
You can not contrast bitcoin and Gold, since Gold cost is controllable and governments are overseeing it, where bitcoin is unstable and nobody has the capacity to upset its cost.