What is the function of user group root?

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http://unix.stackexchange.com – I wanted to avoid using SSH root login to backup my remote server. Thus I set up a non-root user account on the server and place it under the root group thinking that it would possess the same privilege as a root user. But I soon realize that it cannot read files that are not grouped as root and files without the read permission for the group root. My question now is: does the group root serves any special purpose at all? And what is the common practice to backup a remote server (root or non-root)? (HowTos)