Pico-Projector phone, to use or not to use?

I always try and keep my eye out for the latest in mobile technology. Considering that we communicate through email and texting, technologies that we didn’t even really conceive two decades ago, I can’t help but wonder how we will communicate by the year 2031.
How about cell phones with pico-projectors? They already exist, so why not make it so you can communicate via projected screen?
This comes in handy for when you need to swap photos or drag other files from one place to the next. Of course, you will need the recipient’s permission. Check out the video after the jump for more information.
This is currently a research project from the University of Duisburg-Essen in Germany, and I think we see how impractical it is now as it adds much weight to a smartphone. However, even if we could shrink the pico-projector tech so it can fit inside a normal phone, I wonder how practical it really is. I find that I do most of my phone calls with a Bluetooth headset because I don’t want to have to hold something to my ear anymore.
Personally, I see a future where all our phones are nothing more than the size and shape of Bluetooth headsets. Perhaps we can fit this pico-projector technology in there. Now all you need is a blank wall or floor.