There are easy well know solutions to keeping water effectively biologically inactive.
Using distilled de-mineralized water would be a must... and UV is very effective at keeping it biologically inert.
But since water is rather resistant to heat absorption..Glycol AKA "Rad fluid" would become the standard substitute pretty quick I imagine.
Though there are also some more exotic more effective liquids.
But then you are dealing with a closed system that must have fans and airflow and ventilation all over again. Bye bye to your electricity "Savings"

You are correct in noticing the electrical efficiency will be minuscule.
Reliability and service life should increase dramatically...but will probably not offset the huge increase in maintenance costs.
Pumping high volumes of air is always going to be much cheaper than pumping water
And there will never be a better solution to heat dissipation than using mother natures free cold from extreme Northern/Southern latitudes and simple convection.

Further I would speculate the actual added volume/space requirements would be another huge cost for large farms to replace and modify the set-up density.

Bottom line is this a short sighted gimmick. It only give the illusion of increased efficiency.
From a total engineering perspective it significantly increases in-efficiency and risk.
Looks like it was designed to target small scale residential market of hot climates