You know I get the feeling that the thread only sees Warpstone as a combination of fantasy plutonium and magical hard drugs, because that is how the Skaven mostly use it. Just to give one an idea of the vast potential of the stuff and the reason why there is still at thriving black market in it consider the adventure in the 2E RPG book Realms of Sorcery.
In it a doctor obsessed with obtaining magical power uses warpstone dust as well as other unnamed reagents to fertilize grapes whose wine is supposed to make the drinker a wizard. Now the adventure contains all the things you would expect, madness, mutation and spontaneous combustion, but here is the kicker at the end the bastard manages what he planned. If you down a bottle of his special wine, it will give you the talents to be trained a proper wizard, no unwanted mutation, no insanity, just 'yer a wizard'.
Messing with warpstone is a terrible idea that usually works out horribly for all involved, but there is that narrow sliver of cases where you actually get what you want, whatever you want, that keeps the desperate and the ambitious coming back for more.