The pin part of lower quality push pins will deform if you do not get the angle and pressure application down perfectly. I create a bulletin board photo display using these on a cork board which was fairly resistant and not one pin deformed. I was pleased.
Some stores have a 'Community Bulletin Board' so I carry the push pins with me to deal with cork bulletin boards without pins. Sometimes the pins aren't needed but when they are carrying a supply solves the problem.