The "why reason" is easy the video games were hot back then and the pinball companies were hurting and were trying anything to make sales and lure players back to the games. Stern was the smallest company and probably was the one hurting the most so they were willing to try just about anything. There were some truly great games with incredible game play made by all the pinball companies in that era but it wasn't doing much to pull the players away from the video games. Williams and Bally had their own oddball games like Rapid Fire and Hyperball around then too The same sort of thing is happening these days with the I phones and Smart phones and video games.