Pressing seams to one side is a holdover from when everyone was hand piecing. With sewing machines, that really isn't needed. Think about it, when one is garment sewing, all seams are pressed open to reduce bulk. Now, a article of clothing is going to have a lot more stress on seams than a quilt will have. When wearing pants, you sit down in them, bend over, etc with open seams in the construction. A lot of the so-callled rules in quilting are left over from the time when all quilts were made by hand,not using a tool like a sewing machine. The sewing machine creates a much sturdier seam.