The gist of it is the game designers want all the decision making on the fight end and make the jobs have minimal decision making. This is to limit the benefit of clearing specific fights and then having that knowledge carry over to the next set of fights since they want to control how fast people clear content. In fact, most of what they are doing is for more control over the clear rates and how difficult content is that they are pushing. It's one of the pains of a live service game: The goal is to keep someone paying as many sub fees as possible or making as many lootbox / gacha spins as possible while still being enough of a game to be enjoyable by the player. But that is getting a bit off topic at this point.
