The problem is that the places where this technology would be useful also happen to be the places with little to no humidity. You can't pull water out of the air if there isn't any.
The places where this would be useful are places with high humidity, but then water sources aren't usually an issue. You'd have to have a region where it's very humid, but doesn't have access to drinking water. I don't imagine those are particularly common. Such a region would probably benefit more from water treatment than pulling it out of the air.