Calling addiction a disease is good for the anti-prohibition movement, regardless of whether it is an accurate description or not.
Think about what why cannabis is enjoying such success in that area currently. It is partly because of medical cannabis. To win that public opinion debate, all that was required for the pro-medical cannabis people to do was wheel out a severely ill patient and have them recount the wondrous benefit that cannabis was able to give them (after all other respectable pharmaceuticals had been tried and tested, of course).
Who but a monster would deny them that? This I think contributed to the success of the medical cannabis, and partly accounts for the discrepancy between people who support cannabis for medicinal use over those who support recreational use.
Clearly the same thing is possible for addiction, and by proxy, harder drugs. Heroin/Crack/Meth users can be transformed from bad people who have made bad choices into victims of a disease who require treatment and compassion. The anti-prohibition movement need only wheel out drug addicts as the next 'severely ill patients' and they might enjoy the same success as the medical cannabis movement.
Their difficulty will be in breaking the stereotype and stigmatisation against addicts. But if they keep going on (as they are) about "compassion" and "health problem" then they could manage it.
For better or for worse, this is the strategy being played out. The left are putting the right wing in the same position on every issue - as people who just want to hate some misunderstood minority. As it was/is with homosexuals, so it is with junkies. On a more general note, addicts are a special category of poor people and this debate in some ways overlaps with the war on poor people vs war on poverty debate. In many ways and in many cases, addiction is a symptom of poverty. By calling addicts bad people, conservatives allow that issue to be neatly side-stepped and ignored.
I think indisputably there will be benefits to the "disease" side of the debate winning the argument. It will mean spending less on criminalization and spending more on rehabilitation and health care. It will also mean less public stigma against addicts.
It will also pave the way for legalisation, just as acceptance of medical cannabis paved the way for acceptance of recreational cannabis use.
There will be negative consequences though, such as addicts giving up on will power or using their 'disease' as an excuse to use more than they otherwise would. I suppose you have to ask yourself whether it is worth it. Addicts having an excuse to use more VS decriminalisation & higher rehabilitation spending + greater public acceptance of drug users. To me it seems worth it.
If you want to discuss whether addiction is really a disease, go here https://www.drugs-forum.com/forum/showthread.php?t=179171