I use these in my knitting and crochet all the time and not just for stitch marking. I use them to hold pieces together for seaming and to hold shank buttons in place to get them placed to match button holes and other applications where a safety pin doesn't have to have a sharp point.
they keep in place and hold the yarn well
I like them so much I came back and bought another package. I like where you have move the notions to.