Naturally, all LCDs are transparent when their backlights are removed. Same goes for this display. Testing it in a window with some random videos on Vimeo. The window behind it was slightly tinted and the display slightly tints things darker as well. Overall it ends up looking like a stain glass window that moves...very deep rich colors.
I think it would be interesting to create a room with windows entirely covered in displays like this so colorcast different parts of the room via LCD screens. Another note is that they aren't completely optically transparent, you get a slight rainbowing effect and when the screens are off the are solid black.