I expect it’s just a taste thing; water tastes fine but, like, it could taste more interesting if we added a bit of sugar or flavor to it (I was a huge justice fan).

For my own end, it was an easy way to keep my emotions/mood simulated or engaged against my depression that was low effort and easy to supply; that said, I switched entirely to water last year and, now fully comfortable drinking nothing but water and being fairly averse – previously –, I can’t say the previous reasons really make that much of a difference for me, now. Maybe it’s just having drank to my non-water content, already, but drinking nothing but water’s been pretty great and removes low-key health fears I always had.