Interesting concept. I suppose it’s doable in some places. Probably depends a lot on the dew point of the air.
Considering what it costs to dig a well, this could be economically viable if it produces enough.
I’m skeptical that they are able to filter the air and still maintain adequate flow and if they don’t filter it, then it’s not going to be pure - it’s certainly not the equivalent of distillation.
An alternative idea might be to put a reservoir of fluid below ground, then pump it up to a condenser which would be easier to maintain and clean above ground. Could be coupled with a fan to run when there isn’t any wind.
I also suspect that the ground might eventually warm up surrounding the device, limiting it’s effectiveness.
Just some thoughts.
Here in WV, we have plentiful water in springs and creeks, but wells are often very deep and very expensive. But the air is moist most of the year and dew in the morning is nearly always plentiful. So it might make sense if it were cost effective and you didn’t have another source on site for water.
Back in the late 1980's I taught a young man in Kenya to bore wells using a hand auger. After that, he installed a simple homemade PVC hand pump. In 1996 I looked him up and asked, "How many wells have you done?"
"220 and I've installed 40 more pumps on existing hand dug wells."
"How many families use each well?"
"Most about 3 families. Some as many as 10."
"What do you charge to install a well & pump?"
"Depending on depth, about US $150 +/- $30."
This Water-Seer is an interesting device. However, ground temperature down to about 10 feet depth follows the average air temp, seasonally lagging about 3 months. In the arid areas of East Africa, at least, nighttime air temperature is far lower than ground temperature.
Also, in very dry climates, there is little or no condensation on glasses of iced tea (or water, Coke, etc.)