Why is Aeneas's inclusion in the Iliad politically significant?

In Book XX of the Iliad, Aeneas, a prince of Troy but from a minor branch of the royal family, plays a major role in a confrontation with Achilles, as Achilles, after staying out of the war because of his dispute with Agamemnon, rejoins the Greek forces after the death of his companion, Patroclus. The Aeneas-Achilles episode seems unduly long and not central to the action but occupies much of Book XX. Aeneas, as his story is depicted in Virgil's Aeniad, survives the Trojan War to become the founder of the Italian nation and the ancestor of the family of Julius Caesar. As Malcolm Willcock has pointed out in his A Companion to the Iliad, this episode may have roots in Homer's desire to acknowledge a branch of the Trojan royal family in Homer's time that claimed to be descended from Aeneas. Willcock notes that the Greek-Roman geographer and historian Strabo may have corroborated this story in his now lost work Historical Sketches, a work dated much later than Homer's period. More important from a literary perspective, Willcock speculates that Homer's desire to honor the descendants of Aeneas may indicate that Homer is a court poet and therefore reliant on the good wishes of the court to which he is attached.