Well, then you can run as root all the time instead, without creating an user. However, running as root (or giving root privileges for another user) is not only a matter of being hacked via Internet or that your little brother will screw your system. This protection is good even to protect your computer from the most destructive being: the one sitting on the chair, right in front of the monitor and behind the keyboard (you, in the case it was not so clear, ghehe).
Think about the following situation:
- It's very common to move, create and edit files on your computer. When dealing with multiples files at the same time, it's also common to use meta-chars, such as "?" or "*". Suppose you want to delete a file (or a bunch of files starting with "file") and that you are at the root partition (/)
rm * file*
That's great. You've just ruined your system. That will delete all files (*) at the current folder, including those starting with file. Note that there's a "space" between the aster and the file. The correct should be rm *file*.
Also, some applications won't work well, or work at all if you are the root user or has the same rights as the root user. And you don't need to use root user for day to day work anyway. If you ever need to edit a file, use the command "su" and... well, that's it
