Lance Whitney, Macworld:

There are several reasons why you might not want to hold your iPhone while taking a picture: You need to snap the perfect still photo while your iPhone is on a tripod and don’t want to spoil the shot by jostling it. You’re taking a group photo but also want to be in it. You’re too lazy to lift your finger. Whatever the reason, it’s not a problem. There are actually a few different ways to remotely trigger the shutter button on an iPhone.

This is one of those handy tips that’s great to know. Consider setting up the shortcut (as an easy way to get to know Shortcuts) now, so you have it when the need arises.