Earlier quoted context omitted.
It might not stop transactions for drugs, but it might make laundering the money harder and more necessary
It makes money laundering harder for low and intermediate level drug dealers. Netherlands is a major importer for drugs: Amsterdam, Rotterdam, and Hamburg are major ports for drugs. Drug wholesalers in EU would rather transport millions of euros abroad, and use these euros in Africa in order to buy gold and other metals from locals. All of sudden, one ends with gold, sell gold back to refiners and get paid with bank…
Getting around the limitations of cash is no problem for those on the inside. Just like tax havens are only an option for the super wealthy who wouldn't really need them in the first place.