My dear Bort. I understand that desk chair standard activities are not possible on an exercise ball. Neither are they possible in a club chair, a director's chair, a captain's chair, or a stool. Enscootification is particular to the standard and ubiquitous rolly desk chair. Placing wheels on any of the other options is equally silly to me.
Because I would think that using any of the others in lieu of a standard desk chair would and should change behavior. Full disclosure, I am not particularly fond of rolly desk chairs outside of office sport. I would battle for comfy, but non-rolly chairs in my office. Often all of the chairs would be in that format. In my desk jobs I would frequently place things I needed on a regular, but not continuous basis, across the room for me as far away as possible. The point was that I would get up to go to the printer, fax, supply cupboard, or kitchenette. Not just scooty my self over there and back again.
I would think, that if one wanted the benefits of using an exercise ball, for either health or mental benefits, the small amount of effort to dismount and walk short distances would enhance the experience for the user rather than harm it. It is rather the point of the thing: to free yourself from the negative lifestyle effects of being chained to a rolly chair and enscootifying your increasingly ample booty to and fro.
Also, the elegant design of the scooty puff should in no way be compared to the horror of the thing-without-a-name.
Also, also: