On the last 2 years i doubt gold has achieved what bitcoin made, it went from 200-300 dollars to 600-700 dollars, and the potencial of bitcoin remains, and looks like all years bitcoin is getting bigger, atleast on those period bitcoin has just achieved bigger values, something that with gold you arent getting for such. Bitcoin has becames the best investment of the last years, gold has a huge interest, but the results are worse then bitcoin.
You have a good point but that's not the way to compare it, sure that bitcoin has a good achievement for the past two years but in overall it's not impressive unlike gold which has been very stable in the as of now, we can't compare using only the time when it's progressive.