It’s nice to know when we run out of this stuff on Earth, 500 years from now, there is an alternative source.
The value isn't on earth. It's real value is in it's location.
It costs $3000 or so to send a pound of water (or anything) to space. If it's already up there, and not in earth's gravity well, it's a whole lot cheaper.
Gold and platinum and all that crap is just gravy.
Consumables are where the value lies.
I wish the articles on the value of asteroids would point that out.