Even in desert conditions, there exists some level of humidity that, with the right material, can be soaked up and squeezed out to produce clean drinking water. In recent years, scientists have developed a host of promising sponge-like materials for this “atmospheric water harvesting.”
The Sahara Desert has an average relative humidity of 25 percent.
That made it sound like a (practical) dehumidifier, not a (futuristic) personal water harvester.
As far as I know most air trap type humidity stuff works in the desert, just not as quickly as in, say, the jungle.