Your lower back after a long sit
It locks up. Set the arch on the floor, lean back, and let it open the spine. A few quiet minutes is the whole routine.
Nothing to plug in
There is nothing to charge and nothing to turn on. You lie down. The shape does the stretch.
Out of the way when you are done
Keep it by the desk. When you stand up, slide it aside. It does not need a corner of the room.