The way it was explained to me was if pressed open and a couple of stitches pop open you can see the batting and it unravels fast, when pressed to the side if they pop open they don't ravel open as fast and you don't see the batting. I did just do a strip quilt and my MIL pressed the seams open. I left the end to end seams because they are so short but repressed all the long seams to the side.