To show the electron configuration for an atom, what is the advantage of using an orbital notation compared to a dot structure?

The advantage of using an orbital notation is that it shows the electron distribution in shells. 

Dot structures only show the valence electrons of an atom which are the electrons found at the outermost shell. The orbital notation gives a more detailed depiction of the electrons in each shell. This is most advantageous for atoms that have special cases. 

Some examples of atoms that have special electronic configurations are copper and chromium. For example, copper is more stable when the 3d subshell is completely filled. This leaves the 4s subshell with only 1 electron. Chromium is also more stable when its s and d subshells are only half full. The orbital notation depicts these special cases, whereas the dot structure does not.