The Short Version
Samsung's Galaxy Ring can now automatically adjust Samsung AC units based on sleep data, but the feature requires owning both Samsung products.
Samsung's Galaxy Ring can now read your sleep data and automatically adjust your air conditioner, which sounds genuinely useful until you learn it only works with Samsung's own AC units. Buy the ring, then buy the AC, then enjoy the feature you paid twice to unlock. Samsung built a useful thing and then fenced it off from everyone who doesn't own the full set of its hardware.