There is XMR (Monero) which solves the transparency issue of bitcoin and seems popular in the dark web.

I highly doubt I would find any dealer on the street taking crypto tho. Alone the transaction times of 10+ minutes don't fit in a real world drug exchange.

I am not in the business, but would it be practical to use bitcoins/*-coins for this?

Hell no, not even close. You are suggesting using an even more public ledger to do things that ostensibly you NEED cash for.

There is little space for PUBLIC and AUDITABLE ledgers of any kind when discussing private payment.

Thanks! As I said I am not in the business.

My impression is that bitcoins contain a lot of dark money. How is this handled then with regards to sanctions or money laundering for example?

As soon as you want to exchange bitcoin to something real world'ish you are telling some company that the sending wallet is yours, which is now attached to bank details or even more verification. All transactions are public.

Actually I'd be even more worried about the transaction cost "Sorry, I HAD to buy 3 kilos, just because of the overhead. It's a bit like mininum amount for free shipping, you know?" :P