I am particularly pleased that the people behind the design released it to the public so it could be used freely as needed, instead of holding it hostage for exorbitant amounts of money like conventional prosthetics. A 3D hand costs $20-50. Compare that to the cost of conventional prosthetics: $5000 for a merely cosmetic arm, $10,000 for a simplistic hook, and $20,000-$100,000 for a high-performance myoelectric arm. Granted the high-end model currently does things the 3D one can't, but people are already improving the 3D version, and it's a lot better to have something than nothing at all. Regarding cosmetic aspects, children and geeks seem to find the robotic-looking 3D hands cool and appealing. Instead of hitting the "uncanny valley" they hit the "nifty toy" category.
This is what open source can do when you turn it loose. :D