I have them on my mountain bike. One side of the pedal is a regular clip, the other side is a platform with a flat place in the middle that is shaped like the cleat. That way, when I'm trying to get started somewhere between a rock and a hard place, I'm not trying to deal with clipping in at the same time. Or if I think the trail is getting just a tad too rough, being a newbie, I can unclip and flip the pedal over. Then if I fall, I don't have to worry about unclipping at the same time.
Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body, but rather to skid in sideways, champagne in one hand, strawberries in the other, body thoroughly used up, totally worn out and screaming: "Yeah Baby! What a Ride!"