Clipless pedals can help PREVENT a wreck. My sis came to a screeching stop in front of me. I laid on the brakes, and the back wheel came off the ground (picture a reverse wheelie!) If I hadn't been clipped in, my feet would have come off the pedals and I probably would have wrecked for sure. However, I was able to get my body weight back and pedal a few more strokes before properly dismounting.

You don't realize how nice cycling shoes are until you switch back to sneakers for a ride. They help reduce foot/leg fatigue for me.