Celebrities joining in on it raises public awareness. Raising awareness leads to an increase in donations. They're not mutually exclusive. One leads to another. And it's working. In the past 3 weeks the ALS Association have received $13.3 million in donations compared to $1.7 million during the same three week period in August last year, all thanks to the increase in awareness because of the ice challenge.
I can't do it though. I have cold urticaria so my skin breaks out into hives if I get too cold

Thank god I live in Australia.