This design for a retractable doorknob provides extra security for your door by recessing into the doorframe when you leave the house, thereby preventing thieves from picking your lock (there are none). But if you want to get in, you use (we're assuming) the little slot below the knob to extend the knob out so you can turn and open the door. It's all very futuristic and confusing, but still won't stop FBI agents from kicking down your door. [Yanko Design via Geekologie via Sci Fi]
See, I didn't understand at first. Then I read yall's comments.
Basically this is a stupid idea, until they make it retract into the door itself automatically or into the inside knob or something. It needs to be automatic.
And it should read a card with magnetic strip on it to open the door. Like CEOSELF said, this would be great for hotels. It would also be neat if used at home and you could program it to accept particular cards with magnetic strips, not just ones that come with the setup. This way you could maybe use a credit card or bank card. Or even a student card.