I suspect it was far worse than "nothing", not just to our (western) societies - but to people living in third-world producer countries, Afhganistan, South America. It's not good in any way having a major part of your economy based on illegal production and distribution through black markets. That's what the "war on drugs" achieved - worldwide.
So we are going to ignore the harm done by much more widespread drug use in the countries those drugs were imported into?
What - the increased use that remarkably coincided with the increased effort on the "war on drugs"?
The Taliban were more effective in reducing opium/heroin production than the CIA/DEA ever were, wiping out much of the production that was previously tolerated/encouraged by the Mujahideen, who found it to be a useful cash crop with which to supplement western assistance when they needed funds to battle the USSR. You could probably plot a reduction in heroin use and availability in the US (and here) to the rise of the Taliban, but it hasn't stopped there, production is shifting to South America, opiate addiction has been rising in the US again. About 50,000 US deaths per year from opiate overdose. It's a really big problem, and treating it as a criminal problem and not a medical problem has not been working.