I think that to determine the more valuable assets between gold and bitcoin may depend on certain factors especially as bitcoin is just few years now. Bitcoin and Gold have their advantages and disadvantages, and the two assets are actually not really competitors but would complement each other much more. Obviously, and with time in near future, bitcoin may be much more valuable though very volitile.
Again, what we may not deny is the fact that gold has intrinsic material value, and people seem to attribute value to gold for 1000 years. Bitcoin may not have proven itself for so long.