Armor that makes you more stupid. How would that even work? Not exactly fond of it on a concept level. Even if something like that were possible, who would ever wear it? It is just ... wrong ...

Equipment with attribute modifiers are used to specialize our character in the same way our class's default attribute scores do. Attribute sacrifice applies to all non-headgear equipment with modifiers, and counterbalances attribute stacking. It's a game mechanic that gives the player a choice to make. Otherwise, why wouldn't we equip something that gives additional attribute points? In other words, the penalty is designed to prevent us from eventually maxing out all attribute scores, where rolling for success would become nearly inconsequential. There's no fun in always winning!