Time to put to bed an old trope.

Aqua is the one who redeploys Kazuma into the new world but her arrogance and teasing get turned against her and she's dragged into the world to play the Isekai game, she still has her powers though which make her more useful than you think.
As her name suggests her affinity is water and her powers are mostly support and healing, in every world she's a useful asset but having been brought up in a domain that ultimately looks down on humanity, the goddess is too lazy to be useful and knows next to nothing about how RPGs work.
Aqua is far from useless but may as well be for her lack of empathy, any wonder she barely has any worshippers.