I care when the faffing about it disrupts me; when children use it as an excuse to sneak off to the corners for a drink as an avoidance tactic... then the toilet trips... and once one person asks...
I care when they're playing around with them, they spill, or they're upset because they broke.
It's generally good that people drink more than in the 20th century, but having got through an 80s-90s childhood on a drink at breakfast, 200ml on the lunch tray at school and access to a fountain at break, it's a reality that generally healthy people in temperate conditions don't have to have constant access to a water bottle and can go a couple hours at a time of light activity without a drink.
I tend to find it simpler to have a drink from a glass by the sink that's easy to wash at the end of the day than faff with cleaning bottles by hand, and refilling them carefully to prevent leaks, then having something extra to carry/ put in a bag.
The shift to reusable bottles away from single-use bottled water is good, but when people (a minority) treat bottles as status symbols and collections, that benefit is undermined. Some brands have become symbols of consumerism rather than being a practical tool.
Drinking water is not the problem, but people fussing around about it, or having excessive or badly designed bottles can be an issue.
What will be interesting in the future is if the water-generations stay better hydrated for good health in old age than the nice-cup-of-tea age generations. Is habit a major influence or is it more of a changing regulation issue?