If you want to understand which investment is better, you need to "see" the future. Recently there was launched the world’s first public cryptocurrency analytics based on AI technology! This project is called Cryptics. It is able to make a daily and hourly forecasts for the crypto market (Bitcoin, Ethereum, Ripple and more) with 70% accuracy on a base of social media analysis. Right now, you are able to know when is the right time to invest in cryptocurrency. The future has come! If you want to know more -
https://youtu.be/52RacK8L4GIObviously when Bitcoin said that he wasn't literally comparing only the digital aspects of it but also the technicalities behind them.Bitcoin obviously has the potential to replace the current payment system while Gold can only come as close as a barter system replacement.
Bitcoin may be better than gold due to its volatility and high reward to risk ration but gold is a stable asset and long be tried and tested to provide safe haven for inflation of traditional currency. Unlike bitcoins which future seems uncertain.
The future of gold would also seem uncertain if you know the mines aren't going to last forever.You'd be relying on Gold which is artificially manufactured and doesn't really have any value.