Before the adjustment to Misery's potency (900 + aoe) , WHM didn't want to interact with its lillies because it lost 340 potency a minute in exchange for instant MP free healing.
300 potency a minute for 3 energy drains a minute (more if you include dissipation in burst windows) in exchange for Soil or Indom is definitely not as flagrant (Or maybe it is, I don't know anymore), but its still a DPS loss to use, especially when SCH has AF free abilities: Seraph, Whispering Dawn, Fey llumination, Protraction, Fey Blessing, and Recitation.
ED is a tactical choice of course. On the dwindling rare occassions where Soil would
save your co-healer a GCD heal, its probably better to use AF for healing. It gives SCH a certain tactical flair, but its in this weird spot where its potency isn't that significant to feel wasteful, yet its still remains as a potency loss over other more efficient options.
I personally would remove its damage and simply make it give back MP as a call back to the Syphon spell from classic FF. It would still retain its AF dump use, it would just not conflict with Dissipation anymore and AF usage to heal.
It would also make SCH less clunky, but definitely more boring to play.