They can bounce around the earth. They can bounce off of clouds. They can travel great distances with very little power. You can talk to space craft hovering out in space with radio waves. You can transmit, and receive voice, and data in the form of pictures, video, and typed print. You can bounce them off of the moon, and hear the ones that return to you. You can bounce them off of Mars, and hear the ones that return to you. You can use them to quickly warm up a piece of leftover meatloaf. They travel at the same speed that light does. They're the fastest possible way to move information from here to there.