I don't think the enclosure is strictly necessary for this to work. How much light from the object passes through the display, will depend on the switchable dif

I don't think the enclosure is strictly necessary for this to work. How much light from the object passes through the display, will depend on the switchable diffuser's transparency. The lower its transparency during the diffusing state, the less need for the object to go dark. However, they're effectively blocking 50% of the light coming from the object, so an enclosure with additional illumination might compensate that.