Unless you want to load things to the Exchange you don't need any of that stuff in DCBackup OTHER THAN ccmerged. So you can save a lot of space if you have only the ccmerged file in that folder.
Also, if you do load things to the Exchange
1. You apparently don't need the corresponding file in DCBackup if it is store content.
2. You do need the corresponding file in DCBackup if you want the item to load to the exchange and it is CC (not a good idea)
3. If you do have a file in DCBackup that relates to CC then if you load something to the Exchange that file can attach to the item you load to the exchange without you knowing about it.
EDIT: To add qualification to point 2.