two problems with this:

- I would not like to be a customer to an illegal drug vendor who accepts BTC from any other customer

- druggies who use monero congregate on DNMs and onion-only forums, and probably won't come to nostr looking for new vendors to suck off

- if he wanted more money he would have already listed his products on a monero-only DNM. he would be drowning in orders already. he knows this and chooses not to