I'd rather we use mined hydrogen than continue to destroy precious water molecules to get it. Water is an important resource and once split the water is gone forever.
You just burn the hydrogen and receive h2o in return.
And a slightly more complex version of that cycle plays out when the body burns Carbohydrates (literal meaning: molecules of Carbon and water). Water is being split and re-combined all the time in biology.
Quite the opposite, a hydrogen power plant would generate clean water as a byproduct.