Maybe none of us will go, but within the next 20 years, humans will go to Mars and they can tap these sources of water, and/or water ice, to replenish their breathable oxygen. This will enable long-term missions to Mars and facilitate the creation of permanent bases/colonies on the red planet. Bases/colonies will provide the enclosures needed to maintain an earth-like internal atmosphere, allowing for the cultivation of food and eventually, the raising of livestock.
They will also be able to use the water to make rocket propellant (Oxygen is the oxidizer and Hydrogen is the fuel), thereby enabling ships to return to Earth for re-supply of those items that cannot be gotten or manufactured on Mars.
So, who cares?? Just everyone who has any interest in making sure that our species survives long into the future.
When, not "if", the Earth is struck by another asteroid, like the one that wiped out the dinosaurs 75 million years ago, all life on Earth will likely be destroyed. Colonizing other planets will help ensure that our species continues in the event of a global extinction.