The Gemarah says that we hide the Afikoman in order to get the children to
question us and keep them awake searching for it. Yet, what do we answer our
children when they question us as to the purpose of hiding this particular Matzah? If
we want to keep them awake then we ought to hide any object at the Seder Table or
perhaps hide a toy or candy. Why hide the Afikoman?
Perhaps the answer is that the Afikoman represents the Korban Pesach which we
no longer have. We therefore tell our children that the reason we hide this particular
matzah is to symbolize that this mitzvah is now hidden from us and all we can do
is eat this matzah in its place as a reminder of the korban we ate in the time of the
Bais Ha’mikdosh