I gather most players keep Kilrians Shattered Soul for crafting items and relics?
One use I have definitely found for it is in my CLASSLESS character that focuses on fire and lightning damage.
I was struggling to get vitality resist and KSS gave me 20%.
The % Fire and Burn damage was also a nice boost (it also gives % Vitality and Decay if your build can use it)
The % Attack speed was also very welcome.
It’s granted skills give flat Fire damage (and again flat Vitality and Decay damage).
The ADctH applies ONLY to the equipped weapons damage as far as I am aware (stand to be corrected if wrong), but is still quite useful in a CLASSLESS character whereby you are not going to get sort of life leech from Mastery Skills.
In a normal DUAL class build there are usually better options for chest armor depending on your build’s focus, but if it fits with what you are trying to achieve then use it.
One of the beauties of Grim Dawn, there is NO FIXED way in stone to do anything - you can always find combos that seem odd at first, but do amazing things.