Most obviously: it is an addictive substance. It is a propriety of alcohol to get you hooked. The same with nicotine or opioids. If you drink long enough and enough quantity you will get hooked, physically and in all your habits. It interferes with your brain and every other functioning of your body. Withdrawal can kill you because of how the body changes due to alcohol.
You know all this and probably wonder why you could kick other substance (smoking) and not this one. There is a bit of mystery with drugs and addiction. In my generation, everybody tried smoking but not everybody got hooked or not at the same level. Almost everybody drinks, not everybody develops a problem with it. The same way almost everybody is exposed to pain killers without getting addicted, even after trying the strongest varieties such as morphine after a surgery.
However, you don't get addicted if you don't consume it long enough and hard enough. The addiction is developed by the qualities of the substance itself. To me quitting smoking was as hard or more than quitting alcohol. The only thing that makes it easier is the social aspect. Smoking is not well regarded anywhere by anyone. At most, some tolerate it.
In my experience, I needed to accept I could not drink again. Using an analogy of sobermummy (a blog I followed) a cucumber may never turned into a pickle, but once a pickle always a pickle. There is no reverting from there. Once I admitted to my pickle status and gave up any cucumber aspirations, it all became much easier.