I don't agree that gambling can be used as a reference to measure someone's intelligence. Basically most gambling is based on luck, maybe we can do card analysis and counting but nothing is certain, it's all just probability and luck.

However, those who have good emotional control can usually take advantage of gambling. Gambling games usually play more on the emotions of the players, when we lose we become emotional and continue betting to win back the money we lost, or when we win we become emotional/greedy and want to win more by increasing the bet. In the end we will lose more money or lose the money we have won

So, I think gambling can determine a person's level of emotional control, not a person's level of intelligence