Half the buffs/debuffs hunters bring are not personally useful to themselves. That doesn't invalidate them as buffs/debuffs to bring, as our niche is apparently to be the stop-gap for missing buff coverage. There's been many times I've brought a Ravager (physical dmg taken) in SV or a wind serpent (CoE) in BM where it wasn't optimal for me. That's because some people applied these things automatically (frost DKs, and rogues, as two examples), thus to ask the warlock to CoE a single-target boss so I could use a ravager even though the DK has it automatically via passive because the ravager is cooler seems a bit silly.