It's research-in-progress, but I think the promise is slightly different from dehumidifier bags (also in other parts of the world, Thirsty Hippos [1]) which are single use.
You're correct in that: (1) it doesn't break the law of physics; (2) to remove the droplets, you still need energy. But it sounds like if the droplets are moving to the surface, the energy needed to release the droplets could be far lower than most active dehumidification methods (e.g. Peltier junctions).
[1] Thirsty Hippos -- which are very effective in small spaces.
You're correct in that: (1) it doesn't break the law of physics; (2) to remove the droplets, you still need energy. But it sounds like if the droplets are moving to the surface, the energy needed to release the droplets could be far lower than most active dehumidification methods (e.g. Peltier junctions).
[1] Thirsty Hippos -- which are very effective in small spaces.
https://www.amazon.sg/Thirsty-Hippo-Dehumidifier-Moisture-Ab...
Basically a supercharged silica gel.