Okay, I understand your point however I have to disagree in practice for myself since I don't think that something like 8-24 ounces of cold brewed coffee is going to be damaging especially when fluids are being replenished (with the necessary salt included).

For the type of amateur sport I pursue (mountain biking with friends 8-12 miles on an outing) it's quite refreshing and energizing. While long term dehydration is a negative, [based on what I've been learning](https://robbwolf.com/2017/08/29/episode-371-dr-james-dinicolantonio-the-salt-fix/) over-hydration (out of balance with needed minerals) is a greater problem in athletes and the general population.