The device described in the paper seems to be superior to that shown at the link, because it uses a cone shaped display apparatus instead of a pyramidal one. The pyramidal display allows for only three distinct views, whereas the cone-shaped one allows for a continuously varying viewpoint.
Based on these considerations I propose an additional enhancement. Using the well understood technology of privacy filters for laptops, it could be possible to effectively occlude views based on orientation, allowing for the display of several views of a scene simultaneously, with the one visible depending on the user's orientation with the device.
This is exactly how commercial autostereoscopic displays (such as in the Nintendo 3DS) work .
Yes, this is what occurred to me when watching the video. It must know if it being rotated. For the tiger to be seen on the side of the cone you are viewing, it needs to be rendered on the display somewhere between the "nickel" and the viewer.
Someone viewing from the opposite side of the cone would not see the reflection that you are seeing — no tiger on their side of the cone. (Now, in that specific case, two viewers 180 degrees apart, you could in fact render two tigers on opposite sides of the code so both viewers see a tiger.)
No true stereo at all though with the cone. Left and right eye will see the same tiger. Only a sort of "perceived" stereo if you rotate the device.
The video shows them using anaglyphs for this.
Presumably shutter glasses could also be used if you wanted better color rendition.
It is not strictly stereoscopic, but there's an uncanny 3D effect where foreground and background move relative to each other when the observer shifts position. Sort of like paper-cutouts.
The range shown looks comparable to low quality LCDs before off axis causes color shift. People accept those LCDs, seems that angle would be plenty for this purpose since they also let you (appear to) spin the object.
I think it would be more accurate to just call this a transparent heads-up display.
We don't "see" with our eyes, we see with our brain, based on input received from the eyes. The brain itself is perfectly capable of constructing a 3D representation based on the two planar projections that are registered by the eyes.
What makes something 3D, rather than 2D or 2.5D, is that it can be observed from different angles by multiple observers at the same time. It's a fairly trivial test, and this fails it. That doesn't mean its not cool, but it does mean it's not 3D and calling it 3D is plain wrong. Especially when it's something you're publishing a paper about in a scientific publication. This is instead exactly as was commented on: a curved "monitor" that happens to be calibrated to only seem 3D exactly at a single viewing angle, for a single observer, similar to Pepper's Ghost (which only works properly when viewers are positioned at a specific angle to the glass pane).
Bottomline, yes, it's irrelevant. 3D is what feels 3D.
Some thoughts after watching the video. This is way cooler. Since the reflector is transparent, you could put a kinect-like camera in the center (something with depth mapping) -- pointed at the viewer. With some head tracking to "rotate" the display, a reasonable 3d face-to-face chat system wouldn't be impossible since both sides could "see" a 3d representation of the other side, and the gazes of both parties could be looking naturally at the eyes of the other participant (if the camera is eye level).
..but it uses a prism shape, not a cone.