I'm not an expert but I can tell you the effect you saw is nothing to write home about. If you played around with that hologram you'd see there was no changing focal length or exit pupil of the "glass". I LOVE holograms but I've seen the "Hologram Museum" in NYC change locations 3 times probably due to the instantly waning interest in the phenomena.
They are indeed limited. I also think "foil holograms" just look image-y, refraction holograms (like the one you saw) are the best and projection holograms have too narrow a viewing range.
OK, but, the lens has surfaces that are able to change the path of light, evidenced by the dislocation of features on whatever that is it's looking at as the camera moves. Light creating surfaces that bend light that is reflecting off of an apparent object made of light....above my pay grade.