I agree, most likely you would have a shoe on in a self-defense scenario, unless you really like flip-flops. But, all the better, since now you are hitting with the tip of the shoe instead of the ball of the shoe. Is one technique better then the other I don't know. But, using a "pointy" weapon is a nice way of making a quick jab like the front snap kick into a more penetrating kick. When it comes to conditioning, the slow pace wins the race. Learn to form the tool then slowly condition it. You go out on day one with a poorly formed tool and start slamming a pad you will break your foot. If you take your time and learn to do it correctly then eventually the pad becomes to soft and you look for other things with more resistance. I’ve been doing it for years and haven’t had a problem yet.