Too many people think like this: aircraft either crash or not, and if yours crashes you either live or die. (Well, I suppose that sort of unsubtle binary thinking is with us everywhere these days.)

The point of having shoes on is that in the bigger collection of cases in which there is an accident (which may or may not be a "crash" in tabloid terms) or in which an emergency evacuation is necessary, you are less likely to be injured if you have shoes on when you evacuate.