This is a really handy feature that Apple didn’t make a big fuss about but I have found useful. It is a magnifier that can help if you are trying to get a closer look at something, read something small or perhaps make it easier to read something when it is dark.
Some friends I was with found this useful in a restaurant trying to read a menu and they had forgotten their reading glasses. You can also use the light and that helped them too.
Here’s a short video I made to show you how it works.