Someone explain

I see alot of posts about god rolls and all that for every character but something I noticed is on recluse and Dutchess alot of people like magic atk up. I also see people pick up weapon buffs with magic atk up while discarding improved sorceries, Why do so many people prefer this and sometimes even over improved sorceries. I'd like a somewhat detailed explanation so I can more deeply understand but a more simple one will also work