One time I was in Walmart and my mom said I got something on my face but I don't want to get embarrassed. She keeps on telling me to rub it off so I pulled my phone and use the front facing camera to see if it's there.
I took a picture as a blog picture shown above, as a phone can replace a pocket mirror. Very helpful for people are so sensitive about what's in there faces and I don't normally care on what's on my face so much if I'm in a public place.
One time when I was in speech therapy, my therapist made me to use the camera on my iPad to make sure I see myself moving my tounge when I was having trouble with the mouth excercises.
Not only as I know that the front facing can be useful seeing myself as a mirror, it can be also can be useful for video chatting apps like Skype, photo/video taking apps such as Vine, Instagram, YouTube, and the default camera app on your device, can be very useful.