I know you can probably do it with a plugin but that would mean that i would have to configure this every time i set up a new site. So for conveniensce i woul like it to be part of the basic theme i use for every development.
We usualy dont give clients access to administering plugins and themes because that would give them full acces to our in house code base and access to plugins is a whole other can of worms.
This means that the only item under appearance they would have access to is the menu administrator. So in stead of having to go trough the appearance tab, having it at the top level seems more user friendly.