These are sequin pins, meaning that they are intended to be used with sequins just like this... place a small bead, then a sequin (or 2) on a pin and stick the pin in a foam ball. Repeat, many times. They are happy and retro and little bit tacky in all the best ways!
You can use these pins for applique... they are longer and thicker than the pins I normally use, but they would work.