Light doesn’t have a good enough damage cut for one. Have you ever tried using light in TRag and observe how easily they explode? Thunder and wind have options to cover that where light doesn’t.
Does light have absurd orb eating like water does?
Or does it have the team dmg buffing capabilities of Azzy or TPhro Marduk?
Those are the questions, while I’ve already proven that dmg wise other elements compare. And in cases, even outdamage.