It could also be helpful if you run a course every so often and would like a way to go back quickly to compare your times.
I like this idea, I think an organizer of your workouts is what it sounds like. And it would make it easier to find times from doing the workout previously. Maybe when doing entries, an option could be having a title for the runs that you do and then when you need to search for a certain run, you could just look at the titles and find what you are looking for. It could be simple, just having the titles show up on the workout calendar along with the miles ran that day.
I think this is a great idea.