You can finally wash your own back
A loofah covers what one hand can reach. The middle of your back, the spot between the shoulder blades, the lower back: those get a quick rinse and nothing more.
The Sima towel is 47 inches long. Hold one end in each hand, drop it behind you, and pull. The whole back gets washed in one pass, with no brush to grip and no twisting.
People with stiff shoulders, a replaced joint or a bad back say this is the reason they keep it. Nobody else needs to help.