Actually I think there might be some truth to that. By putting your feet on the bench when you lift you will be more apt to push the weight with just your chest and tris. When most people bench they use there feet to help drive the weight up. I'm not saying this is right it just seems logical to me!!
At first you will be weaker because your feet dont drive the weight or stabalize you. I would say don't do this just because if you tip slightly sideways you can hurt yourslef or people next to you
then do floor presses............. makes you lay flat
if your feet are planted flat you may still push
also having your feet in the air or on the bench will throw off your stability and cause you to have to worry about that while you are benching........ you dont need that