If we drop the math and look into the core of ST spells vs AT spells, we can clearly see that ST spells have much more soft/hard CC effects embodied in them, while AR have very few and mainly soft.
Meaning, that for them to be effective - a controlling effect on the enemy should yield more impact than straight up attacking it. This usually means bosses without sidekick crews, which are SEVERELY underepresented in bg3.
Why do they feel bad to use in BG3? Because there are no ideal situations to use them. Simple as that. Not because some numbers are wrong, being stats or calculations or anything else.
