Before playing basketball, Dirk played handball and tennis and even managed to get into the German junior tennis rankings but he quickly got tired of being called a "freak" due to his height.
I often notice that trait in sports stars, that they played various sports growing up, which helped them to improve different aspects of their game.
I think they dont start playing different sports taking as a goal to help in different aspects of their game.
They are just kids finding a sport they like to play.