The phase transition of liquid water to water vapor causes a substantial drop in temperature. We all know that - it's how the human body cools itself through sweating.
Using a micro-layer of water on the heat exchanger lowers the water circulation of the system to less then 1% of comparable water-cooled systems. It enables to mitigate most of the water-cooling drawbacks without added complexcities.
The small water needs enables the use of Reverse Osmosise water It further mitigate system drawbacks and makes consuming reusable water possible.