The accessory triggered proc attack is actually separated from the damage source. While this doesn’t matter much in most circumstances, knowing this allows for some interesting battle shenanigans.
For example, dropping a multihit attack on a stationary monster/ turret while running around monsters, the proc AOE from the accessory set will hit the monsters which helps a bit in gathering aggro especially for the attack distance challenged melee builds.
This might be good classes with delayed multi-hit attack skills, such as Taoists and their Creeping Death Charm. Due to the charm’s hit area and the number of hits they do, they are superb for hitting “targets that don’t move much at all”. Couple with the accessory set on a stationary target and we might see more black spheres while getting ourselves surrounded by monsters somewhere else.