Data researcher Antoine Le Calvez has been tracking the movements of BCH and BTG on forks.network since the coin splits came into existence. His figures show that three times as much bitcoin cash has been claimed as bitcoin gold, which was born three and a half months later. A series of charts track the amount of BTG and BCH that were moved following the respective forks. In other words, they indicate the amount of each coin that was claimed by bitcoin holders. That figure stands at 2.2 million for BTG but 6.6 million for BCH.
you can not even start to compare these two!
bitcoin cash is so much older than bitcoin gold, not to mention that there is still no easy way of claiming your bitcoin gold compared to BCH. for example BTG does not yet have an SPV wallet but BCH had an Electrum fork from early days that most people used to simply claim their coins.
also the amount of advertisement that BCH did is huge. in comparison many never heard about BTG for weeks after the fork happened!
and finally it is the price factor. BCH went to nearly $2000 and that is enough incentive for anyone to try and claim the "free money".