I wouldn't find that unusual. I hardly ever drink water; if it's available, I drink milk. Why would you drink water?
Water has zero calories, is reasonably filling, neutral-tasting, and gives me what my body needs, without any other junk. What's not to like?
Also, what you think cheese consists of.
One can enjoy something without it being good for you. I like cheese. I'm under no illusion that it is healthy
If you're replacing sweat, wouldn't you want sports drinks?
https://www.gocomics.com/peanuts/1969/03/27
But anyway, in most cases, the fact that drinking milk doubles as a source of food is clearly a benefit. It's hard to explain a common behavior by reference to a rare circumstance.