What's the difference between the main document window and the diary?

Problem: I expect that when I import new workouts into the main document, the main document should behave like a journal. But on the other hand there’s the diary where I can enter additional information on workouts. Why are these two separated?
Explanation: Unlike pure journaling applications, TrailRunner has two modes. The route planning mode and the diary mode. These two modes are separated into the main window (with the primary focus on building a network of tracks to plan routes within) and the diary (with the main focus of archiving the raw data of recorded workouts). Even though seperated, TrailRunner still displays workout information for a selected route in the main window (if a related workout can be found in the diary).
Advice: When you import new workouts, make up your mind, if the workout course contains track segments you would like to add to your network of tracks. If so, use one of the merge options. If you (just) want to archive your workout in the diary, check the add diary option.
Tip: Unlike the main document, your diary is stored in a central location on your Mac. As you can have more than just one document, each of your documents could cover a different networks of tracks. For example you would like to have one document for your neighborhood and more for each location you where on holidays.
Additionaly, if you delete a route from the main document, it would not delete any workouts in the diary and vice versa. Both are a separate thing even though they might be related to each other.