I use water cooling to remove heat AND humidity. AC doesn't do this as well or consistently- and as mentioned above, its far more costly to operate on a head to head basis.
I've cooled 16kW of sealed and vented lighting with just one 2 Ton chiller, and it cools up to 12kW of open bulbs. That just doesn't happen with a Freon to air exchanger.
Moreover, one chiller cools multiple spaces, spread apart. AC can't do that. Water chilling also cools with less space, a phenomenon known as energy density- the same principle underlying liquid cooled laptops and car engines. Because I work with vertical systems, my ratio of total room volume to canopy surface area is radically different from flatlander style grows. This results in rapid heating, potential hotspots and a very high transpiration load in the room. Water chilling is essential to effective management of these environmental issues, AC is a nonstarter.