I can accept bizarre. I think it is safe to say all drugs modify the physiology of the user in some way. The difference is if that change to the body is what induces a craving for more from a cellular level. There is no indication that depressants, as a class, achieve addiction purely in response to cell modification.
You mention cocaine versus opiates. A major difference there is that cocaine doesn't require repeated use to be addictive. It is immediately addictive and may result in drug addiction even many years later: https://en.wikipedia.org/wiki/Cocaine_dependence#Risk
Opiates are not immediately physically addictive. It takes repeated dosage for addiction to set in. Typically this is a result of pathological changes resulting in a combination of modified neuron-physiology and adjusted behavior. For depressants to be addictive it seems there must be some manner of behavioral persistence that drives the user to continue consumption in addition to physiological adjustments. If the drug is not immediately addictive the user must then use it repeatedly to build addiction.
There has been research that indicates this is the pattern of addiction for cigarette use even though the primary drug present is nicotine, which is a physically addictive stimulant. While nicotine is physically addictive not everybody who smokes cigarettes becomes a dedicated smoker. It takes more than the physical addiction to nicotine. This has been identified by research as well, and much of that research indicates it is a combination of certain demographics and personality profiles that most likely triggers cigarette addiction. This research indicates these individuals are identifiable and their degree of addiction prevalence is predictable.
While cigarettes are not depressants the point illustrates the difference between a purely physically addictive quality and actual addiction in practice.