"Anecdotal sources describe coconut water is used in India for the senicide of elderly people, a procedure known as thalaikoothal.[13] In this custom, the elderly person is made to drink an excessive amount of coconut water, eventually resulting in fever and death, the exact causes of which have not been determined.[13]"
It's well-known that green coconut vendors are very common in India (https://commons.wikimedia.org/wiki/File:Tender_coconut_vendo...). They have a cart of coconuts, chop the top off of one as you watch, and hand it to you to drink. As a tourist, it seemed to me to be safer than drinking water.
So, to the original point above, coconut water is not waste, and is quite refreshing, and fills a useful niche if you're worried about stomach bugs.