If you ever or have an android phone with a broken screen, that you want to recovery things off, i.e. photos etc.
Most android phone have OTG (On The Go) enabled.
What this means that using OTG you can control your phone using an standard USB mouse, this is where the OTG comes in, it is a cable that connects to your phone (see below about £10)
You can also connect a external hard drive (formatted as FAT not NTFS) or card reader or if you want an keyboard.
Once you connect a mouse you get a cursor and you can control any part of the phone using the mouse, ever swiping, so if the touch screen isn't responding because it is broken. It is a little weird using the mouse at first because you want to use the screen to control it, but after a few minutes it OK.
I haven't tried this on an iphone or windows phone (doh, no one has one of them), so i am not sure if it works on them.