Not at all, just saying there is the alternative, and that spell happen to have the highest base spell damage of all the spells available to the Necromancer, except PB + Chill which is marginally higher. I don't know the coefficient though.
It has its uses though they are few. Mostly trash mobs, but at Thoth and corpses too. Your build is perfect, and there is not enough points to take Plague Swarm if you intend to use Reapers or Blood Arcanists.