Intelligence

Intelligence plays a huge role while playing this game. For example, the Villains team thought they had the voting all figured out. Russell was smart and had the immunity idol. This made them think that he will be pressed to use the idol. Instead he was smart and gave it to another tribe member and saved her. Everyone thought he would go home and it would have been except for Tyson. He voted for the girl instead of Russell like they planned. In the end, got sent home. 

Intelligence is necessary to win the game because they need to come up with strategies for challenges and tribal council. Also they need logic when it comes to making alliances.