But at that time (2012), it's like it was only gambling platforms that recorded the highest transaction for Bitcoin because not much business were interested to add Bitcoin as a payment options and many people were still so skeptical about Bitcoin while so many people saw it as a scam. If it's now, you can see how so many institutions are not adopting Bitcoin on like before when they showed no interest. Regardless of how some institutions have adopted Bitcoin now, there are too many crypto casinos that is accepting Bitcoin for gambling.
The bitcoin transaction was not monitored by any of the government or private companies.So it was the foremost reason used by the gamblers to use the bitcoin in 2012 for the transaction in 2012 and even now.Now the cryptocurrency based gambling sites are in the market in large numbers.Along with the cryptocurrency growth,the growth of the cryptocurrency based gambling sites also reached the peak in the market now.Now many gambling sites had uses various kinds of crypto currency for the transaction along with the bitcoin.
The transaction in Bitcoin and other crypto is more efficient and fast for so many players that's why they continue using it but it seems like no body wants to risk so much of their Bitcoin but rather wants to hold it for making profits. That's why there has been other smaller crypto being added by casino so that those that still wants to bet with crypto can use another altcoins and not Bitcoin that they might want to spend.