I used to work for a company making a similar device, the chemistry behind the technology is actually a well researched topic, and there are many kinds of various chemistries that can achieve a similar effect. Silica gel packets are the most common, a cheap solution that extracts moisture from the air, but is non-reusable.

These MOF compounds are useful because they have a fundamentally different method of collecting the water molecules. The framework traps the molecules inside, which can be later released with heat. Thermal solar power is free, but does require careful management of the rest of the device such that the material can get hot enough (usually around 100c), which also providing another surface to condense the vapour. I spent alot of time designing such panel

There truly couldn’t be much of a downside to these technologies. The real alternative is desalination, which produces hyper concentrated salt pools, or well water extraction, which is also bad…

The reason these technologies is usually due to the cost effectiveness to produce the material, and to build the enclosure around the material.