How can five cents help save a child’s life? Not by being in this envelope

How can five cents help save a child's life? Not by being in this envelope

The Leukemia and Lymphoma Society sent me a letter with a nickel adhered to it. The letter goes on to say that they included it to make a point about how nickels add up. I give them kudos for novelty, but not for practicality. Considering how many letters the society sends out, how many nickels are NOT adding up to blood cancer research?