How does Macbeth's death impact the play?

With Macbeth's death, the play ends as it began—with a victorious battle in which a valiant hero kills a traitor and holds high the severed head. The first we hear of Macbeth in Act 1 is the story of his bravery in battle, wherein he decapitated Macdonwald's and displayed it on the castle battlements. At the end of the tragedy, Macbeth—himself a traitor to Duncan and his family—is treated in exactly the same manner. After killing Macbeth, Macduff enters with Macbeth's severed head and exclaims "behold where stands / Th'usurper's cursed head" (V xi 20-21) The play thus ends with the completion of a parallel structure.