If my information is correct, coils back in 2.0 was intended for savage players. It wasn't until HW that they released both normal and savage raid tiers. I think it was mainly so casual players could also experience the story and have another alternative to gear up.

What someone might be able to clear up for me is if I'm even correct. iirc there's an NPC in revenants toll that unlocks (savage) versions of some of these fights. Are these even more difficult fights than the 'normal' savage modes?. so to speak.