What is advantage of backing up a filesystem by version control software?

Version control software seems to be used for backing up project mostly in plain text files. For backing up a file system, with large amount of files or large size, regular file copying/transferring software such as rsync seems to me more proper? If not, what is the advantage and disavantage of version control for backing up a file system? How is version control worth more than regular file copying or transferring software?