Useful, much better than hand washing. Hand washing is impossible in many places. If you wash your face, you can wash places that you can't usually wash to make your skin cleaner. If you say that washing thin hurts the skin, there will be, so many face brushes can't be used often, but some face brushes are harmless to the skin. For example, Job uses microbubbles to clean, that is, water molecules, which are gentle and won't wash thin the skin.