PAA – Harry beats Voldemort because he has the allegiance of the Elder Wand because he disarmed Malfoy who had disarmed Dumbledore. However, Harry didn’t win the Elder Wand from Malfoy; it was just Malfoy’s regular wand. So why would Harry have the allegiance of the Elder Wand?
It seems that the way to win the allegiance of the Elder Wand is by beating the owner in a duel, regardless of which weapon used.
The question is really why Harry needed the Elder Wand – if Harry died to save Hogwarts as he did, and because of that the power of love was used to save everyone (although they were older than 17, ??”?) so that Voldemorts spells couldn’t affect them, and if Harry’s blood was still alive in Voldemorts veins, and therefore couldn’t be killed, why did he need the Elder Wand?