Granted, Genghis Khan was actually one of the best things to ever happen to Asia, and could have been great for more of the world had not various events kept his Empire from growing stronger and remaining strong longer than it had. Just not nearly for those reasons.
Among the things his Empire did was practically eliminated banditry, which opened up trade vastly, because now merchants could not only travel freely without having to pay taxes to various kings and warlords to pass through their land, only to a single entity who taxed them only once, but also didn’t have to hire large protection details to protect themselves from bandit colonies, but also from those same kings and warlords. Genghis Khan and his army did not tolerate bandits. Genghis Khan didn’t tolerate bandits within his army, most particularly.
One contemporary of the Mongol Empire even wrote that one could walk from one end of the Empire to the other, alone, with all your valuables carried on your head, and never once be accosted by anyone trying to take it from you.