Ya, Cocaine has almost no physical withdrawal profile.
I used to go on binges where I would IV up to an Ounce of acetone washed blow (95%+pure) in a week or so. Yes I would feel like shit after but generally I would sleep for like 20 hours and then be tired for a few days.
Barbs are so seldomly used now a days in the Western Hemisphere other than occasionally for seizure disorders and were basically wholly replaced by Benzo and Benzo-like drugs because they were marketed as a safer alternative with a higher theraputic index. Although there is some truth to this they still have a bad WD profile if not titrated off of properly.
While Alcohol, Barbs and Benzos are typically more dangerous to go cold turkey off of, the W/D for all of these is incredibly easy to manage with Benzos or just titrating the dose downward.
Someone on a high dose of street opiates who does not have a prescription is much harder to stabilize because methadone induction takes weeks or months and suboxone has a ceiling dose and will do nothing for someone with a huge habit and precipitated withdrawal is another possible complication altogether.
It is also a popular myth that you cannot die from opiate WD alone. There are thousands of recorded cases worldwide especially in places like Russia or the middle east where heroin is widely available and methadone is not an option.
The simplest way I can put it is this: Person A is huge alcoholic who has been drinking half a gallon of Whisky a day for years and Person B is Heroin/Fentanyl addict who has a 500 dollar a day habit. They both check in to a medical detox.
Person A is prescriped large amounts of Diazepam or Librium and then the dose is reduced slowly. They have cravings and feel uneasy for a few days but are generally doing well
Person B is prescriped Clonidine, Benzos, Muscle Relaxants, Pramipexole or Ropinirole and other ancillary drugs to treat symtoms. Their habit was way to high for suboxone and if they want to go on methadone they can but the max starting dose is 30mg a day and you can only go up 10 or 15mg every 3 days. Person B is going to be in absolute hell for at least 5 days if they chose methadone and probably 10-15 days if they chose to go cold turkey all while thinking if they could just get one more hit they will instantly go from feeling like offing themself to euphoric bliss.
TL

R. Drugs are Bad.
Keffals will almost certainly relapse because it takes a lot of hard work, humility and self awareness to be successful in recovery and Keffals is a lazy, self centred idiot.