This coin is not a bad idea, but I never liked the cleanwater charity group because just focusing on giving people clean water is not enough.
Most smart people in 3rd world countries will boil or filter unclean water, collect rainwater and water from clean sources, they will not drink out of puddles in the middle of a paddy with a cow standing overhead like some pictures suggest.
Another thing, if your life really sucked and you have spent all your life drinking filthy water, you wake up the next day with cleanwater, would it really matter? It still doesn't change much.
What is important are the people need to be educated, then gain employment so they can afford decent dwellings. That is what charities should focus on, building up the local economy.
Waking up and drinking clean water will drastically change your entire outlook on life. Our bodies are made of water. So if you drink polluted water you become sick, unable to be productive, organs shut down, then you eventually die. So how can you work, provide, teach, learn, or be active when what you are putting in your body is killing you? Even worse, what if you little child died because it was not developed enough strength or immunity to drink the toxins it is taking into its body? How would that affect you're ability to function. Most places in the world, especially the ones Charity:Water focuses on, have no means to simply build up a local economy. We are talking about war torn countries where children are kidnapped and turned into soldiers. Or nothing to draw an economy off of. Collecting rain water is your solution? Have you been to, seen, or even heard of places that doesn't get rain for months on end? Some people have to travel miles per day just to carry polluted water back to their children.
Furthermore, the "educate and build an economy" concept is pretty far fetched. Capitalism is not the answer to every problem. Some people have lived their entire ancestry without the need or use for money. They have lived off the land, provided for their families, and been happy. Then along comes war, rebels, murderers, and worse capitalists. Some come through and slaughter tribes and peaceful people making it impossible for them to access the things they have used for centuries to provide a sustainable living. Sometimes entire governments sell of the land they are living on to capitalists who truly believe that cutting off access to clean water and charging these people for something every human needs to survive isn't a crime. Look at what is happening in India with Nestle and Coke.
So to answer your question, "Would it really matter?" Yes, it matters, it makes every bit of difference in the lives of people truly afflicted by the sinful nature of mankind. It matters to the child who goes days without drinking water at all, or the mother who lost her baby to polluted water. If your life sucks, all it takes is one ounce of compassion, or one problem solved to figure out the next step in fixing your quality of life. When you wake up hungry and thirsty you can't think about anything else. You can't build a school, or an economy, you are too weak.
Clean water is one step in helping, while there are many problems to be solved, you cant take on everything at once. You have to take steps.