I tested that option sometimes and I needed to undo the changes, is because an RPG allows you to do the same thing in different ways and I always preferred mine. I think this option works as a tutorial for new users or casuals, but no one ends up using it.
Indeed, in the end no one using it, so please Larian, don't implement this "auto-assings button" !
Better spend time on more intresting things (enough work to do, I can imagine!) for Original Sin !
If I'm stuck in the game with something I first search a solution myself and if no answer, I ask on this friendly forum ! Voila, problem saved !