TortoiseSVN Why does "Add" exist when you can commit unversioned? : I can't seem to get a clear answer as to why this is useful.

**[Official Description][1]**

> Add files, directories, or symbolic links to your working copy and schedule them for addition to the repository. They will be uploaded and added to the repository on your next commit. If you add something and change your mind before committing, you can unschedule the addition using svn revert.

But versioned files will still be uploaded even when you don't add them. I have never used this feature and historically i have always been committing versioned files. So what's the point? What am i missing?
  [1]: http://svnbook.red-bean.com/en/1.2/svn.ref.svn.c.add.html