Pros: Cleans the ball, keeps moisture in
The plastic cover is very flexible and allows you to wrap it around the ball and scrub easily. If you wet the inside and keep it in a pocket, it will stay damp for at least a couple hours, even in the heat, and your pocket won't get wet.
The cloth material inside is very soft. I would actually like it if the cleaning material where a bit more coarse to make the scrubbing a bit easier, but sufficient pressure will definitely clean the ball.