As a time traveler, I routinely commute between 1968 and 2016. So I often have to set my iPhone back before 1970. Just because you can't see a reason to do this to your phone doesn't mean nobody does. I really wish people could be more thoughtful when they post here.
The next time you travel back to 1968, visit 13-year-old Steve Jobs and give it to him. Show him what it does. Tell him to make sure he doesn't sell it for weed. Also tell him to watch out for a geek by the name of Bill because he may try to steal it. I'm curious how much more advanced Apple's technology would be by now in this alternative timeline.