Roofhopping or parkours is a sport made to look cool. It gives you a better vertical speed, you may win against someone running through stares (or maybe not depending of his condition). But the horizontal is not magic, you jump obstacles the fastest way possible but you could just have chosen a better way at the beginning.
A normal human doesn't have the strength, the agility and the cold blood to execute the most basics move. It is not an accessible sport, it require a lot of skill and training. You have to practice in safe place hours before trying moves in dangerous place unless you want to die young.
Also you expose yourself to multiple injuries and you risk your life.
Le Parkour is an extreme sport, it will never be widely practice and it is not a safe way to travel.