Can I use Dropbox Backup to backup files stored on Dropbox?

I use Dropbox and Dropbox backup to sync and backup files on my two Mac laptops.  Recently, I asked a question because I was confused about how Dropbox works and I received two good answers that cleared up my confusion.  After reading those two answers, I think the best way to keep all my files in sync between my two Mac laptops is just to move all of the files and folders out of the Documents and Desktop folders into dropbox.com and have those folders synced to my two laptops.  What I don't want is to have to move files to my local Dropbox folder in order to access them between laptops as I need to access too many files on a daily basis for this to be efficient.

But this raises a new question.  If I start storing all of my files in dropbox.com, can I still back them up using Dropbox Backup?  I'd like to use backup so I can easily restore files I accidentally delete, or roll back to an earlier version of a file.  However, when I open the Mac Dropbox desktop app and go to Preferences > Backups and click the "Manage backups" button, if I scroll down to "Adjust settings" and click the "Change folders" button, the only folders shown are my main Mac System folders (Desktop, Documents, Downloads, Music, Pictures, & Movies).  I don't see a way to tell Dropbox to back up the files I'm storing in my local Dropbox folder (/Users/me/Dropbox).  Are Dropbox online storage and Dropbox Backup mutually exclusive services, meaning you have to use one or the other but you can't use both?  If so, this would seem odd as I can see a definite need to be able to restore or roll back files regardless of whether they're stored locally or on dropbox.com. Thanks.