When you are going to call your sister up and bark "Happy Birthday" into her answering machine, a cell phone is no end useful.
Some years back I encountered a flasher on Forbes Avenue in Squirrel Hill.
It was Saturday evening. Squirrel Hill is a big Jewish area, and the orthodox and Chasidic families were all out in their best. I didn't think they needed to see the poor guy's willie. (No I don't remember if it was circumcised.) So, I found a pay phone and called the police and gave them a description.
If I'd had a camera phone I could have snapped a picture, and passed it on to Pittsburgh's finest.