I ran all over Creation barefoot as a kid. He's not wrong. Your feet toughen up, and you're aware of what you step on.

On the other hand, I've worn work boots since high school, and wouldn't give them up. (Literally! Uniform required penny loafers or better. I got chewed out more times...) Callused soles won't save you on sun-hot asphalt or gravel, and knowing what you're stepping on won't do you a lick of good when 120 pounds of server and handcart run over your toes.