Me too i do not use bitcoin to evil work specially in buying illegal drugs.. but nowadays i know that it is working..many retailer or big businessman as well as the druglords use bitcoin in buying illegal drugs, and i know it is usually done on the blackmarket and on the deepweb. And also even the other illegal transactions bitcoin was used by the powerful individuals. But in advantage it can use to buy legal goods, used in legal transaction and used to buy legal drugs which can help on peoples health and ofcourse on the  legitimate and legal stores.