For me, they're great in practice. And I don't live in a dry climate.
I'll do anything to avoid living in a humid place, though. I can take very hot temperatures, but not hot and humid. At least when it's hot and dry I can still enjoy the outdoors.
The places most in need of cooling are those with high wet bulb temps, which are typically high humidity places. I've lived in the south east USA my whole life, and I cannot even imagine adding more humidity to my air.
For me, they're great in practice. And I don't live in a dry climate.
I'll do anything to avoid living in a humid place, though. I can take very hot temperatures, but not hot and humid. At least when it's hot and dry I can still enjoy the outdoors.