The nubs chew holes in frame bags, and there are plenty of other options. the seat tube and seat stay positions do not require a peg if the pump is sized well either. It was also a place where I could shave a bit of cost on something I or many of my customers never intended to use. I know there are a few folks that wanted one, but there are ways to work around it missing, and the only work around for it being there is a file.