In my opinion, WaterWetter falls in the same category of most (if not all) miracle products sold in plastic bottle with the assurance it will solve all of the world problems.
Gasoline additives (with the exception of very very few injector cleaners)
K & N filters.
and tons of other product sold only as the result of very effective and brilliant marketing campains to people looking for solutions to question nobody ever asked.
A car is not designed to overheat. if it does, there is something wrong with it. Instead of putting a questionnable band-aid to the problem, I,d rather go to hte source of the problem. (unless such product is used solely to postpone the repair.