> By definition luxuries are not necessities. If people can do without them fine (millions of people don't drink or smoke), they are not necessities.
I daresay, it's a necessity for human beings to experience less than complete absence of all pleasures in life. Many of the things described as "small luxuries" are individually forgoable, sure, but for one to live their life denying themselves the satisfaction of any expense anyone else might do without, experiencing nothing but the bare toil and drudgery required for physical survival, is a kind of mental torture no one should be expected to bear.
If a drink now and then (or "junk food" instead, or movies, or videogames instead, or nice clothes, or this, or that, or the other thing, whatever the particular indulgences are that floats one boat) is what it takes to feel like a proper human being, it's worth it. Poor people like the same things anyone likes, and I cast no aspersions on their allowing themselves joy.
(Also, yes, millions of people don't smoke, but at the same time, millions of people wish no longer to smoke but have great difficulty quitting, because it is physically addictive (rather famously), and though one might say no one should ever have picked up the habit in the first place, it's not uncommon for perfectly fine people to have made suboptimal decisions at at least one point in their life...)