smart people will never answer this question) in America probably this is already a common thing.
There is no benefit of buying drugs, drugs is only destruct human body. Spend bitcoin only for buy that disgusting goods is not wise. It is the same as replacing a prosperous future with deseas-filled future. I prefer like to save my digital gold/bitcoin.
Drug is dangerous for human health and it is not allow making drug business using bitcoin in a lot of countries. So before you are going to start this kind of business with bitcoin just be sure bitcoin is able to put in it or not, and selling drugs is legal or illegal in your place so if it is not legal then you should go for some other business like fabrics and food selling with bitcoin or whatever skill you have can use for bitcoin business.