How did the nomadic aspect of mongol society contribute to its rapid expansion?

Being and living on horseback enabled the Mongol society to advance faster and further as any other nomadic society before. They had excellent leadership with Genghis Khan leading this once a collection of tribes into the biggest Empire the world has ever seen so far. Being nomads they didn't need any official space where they would settle but rather they could just conquer and conquer the different nations in Asia and Europe.