Importance, as beauty, is in the eye of the beholder.
In my opinion, repeat - "opinion", there is no such thing as wasting water. Remember the water cycle? Its not like it just disintegrates and goes away.
That being said, what you are "wasting" ("using" is a better word in my opinion) is the energy and resources involved in providing that water to you and processing it after you are done with it. If you are happy with the price you are paying for those resources, and the providers of those services are happy with the revenue they are receiving, then no one else's opinion matters.