Nobody knows how much gold in the Earth else. So it is less predictive. Bitcoin is more clear. Therefore, it is more promising and its price will grow further.
It's not less predictive it is even more predictable because there's a lot of use we can do with gold for our jewelries and other stuffs that makes it precious if does have gold. But in my own choice, I'll go with bitcoin I simply don't have gold and I can have it now for earning some decent amount of bitcoin.