I wonder why the mechanism was so interesting/highlighted with a transparent housing (glass dome) for the user to see? You would think it would just be put in

I wonder why the mechanism was so interesting/highlighted with a transparent housing (glass dome) for the user to see? You would think it would just be put in a simple opaque box, as the output tape is the only thing of interest. Did it frequently jam and require diagnosis, so a glass dome helped? Or was the mechanism to be appreciated, like a fine mechanical watch?