I think you are perfectly right considering the tournament, in which you can get a critical hit with every attack. Still a lot of people including me have the feeling the chances are bigger with a dominant element. I know this is not true, but sometimes you grasp every straw (dutch expression, probably different in english)
For the battlegrounds, dominant element is important, because there you have the defensive win, and chosing the dominant element matters in my opinion.
Anyway i am glad that nature flashes strong again against earth, meaning my sloth and vinotaur are coming back in the arena a lot of times.