A possibly more practical use would be to invert this setup. I have a big window that faces west, which means I have to close the curtains if I want to work in my apartment in the afternoon. This system could be set up to block the sunlight specifically from getting in my eyes (and on my screen, whenever I'm at a computer), but still allow the room to be lit.
What's particularly amusing is that this "curtain" has a function that's the opposite of increasing privacy.
This isn't my work, just linking to it. Very cool - though not exactly working for the purpose he intended!