These little ejector tools are useful for more than just SIM cards. CD/DVD ROM drives have force eject buttons inside tiny little holes that these can reach and push. Many hardware reset buttons are also hidden inside tiny holes.
You could use an unfolded paperclip in a pinch. One of my air purifiers has a reset button inside a hole that is slightly too thin for the paper lips I have on hand. But the SIM ejector tool I keep around fits perfectly.