It's not really a steering wheel in the sense that you rotate the wheel to turn the bike, because the wheel is attached to the stem along the ring, while a car steering wheel rotates around the center of the ring. The biggest advantages seem to be that you can quickly grasp this ring anywhere for quick movements, and you don't have to worry about getting impaled in a wreck.
I'm surprised I haven't seen one of these mounted on a fixed gear bike up in San Francisco.
I wonder if this bike is a fixed gear -- the hub looks too small to have a freewheeling mechanism in it.
Thank you to Mike for this!