A player's time and effort is worth something too.
I can confirm that 3% assault and 600 ATK are essentially equivalent at current levels of base attack and character attack for a typical player with a "maxed" grid. Meanwhile, Rush is worth at least half its double-attack rate up % in damage in most builds. Consider that upgrading from a perfect SR accessory (ATKx2) to a perfect SSR accessory (ATKx3) would give you less of a damage increase than this.
Well, if you're spreading your effort among 6 elements, maybe such compromises are necessary. I wouldn't know.