[Yark]

I feel the need to point out that God Rod won't let you cast Nature spells with it. Only Mercalan domain ones.

Again, the point is that the staff is objectively inferior to Bloody Palms. There is no justification for using it, and you're only proving my point by highlighting what a pain in the ass it is to actually cast Nature spells with it equipped. Would you rather use Overgrown Staff + Tome, or Tome + Bloody Palms? The answer is obviously the latter, because adding a small, flat increase to spell power is outdated and underwhelming. It is the same reason that the item mentioned by the OP is such trash, and is the reason I chose to bring it up here instead of making a new thread.

Let me put it this way. Even if Overgrown Staff always gave +40 spell power without any other conditions, it would still be inferior to Bloody Palms. Why should this be the case?