Richard A. Jensen relates the following story about the importance of genealogies:

There is a story told of a man who translated the Bible into one of the many languages of the people of Papua New Guinea. His translating procedure was to translate a passage, have his assistant read it to the people, and revise the translation accordingly. In doing this the translator skipped the genealogy for the same reason we pay so little attention to it: boring!  At the end of the task, however, he did translate the genealogical list and he was present when it was read to the people. As the names of the ancestors were rattled off the translator noticed that a hush fell over the room. So quiet did it get with the crowd pressing in on him that he thought he must have violated some tribal taboo in his translating. But no! When the reading was finished the people stood in amazement. "Why didn't you tell us this before?" they asked. "No one bothers to write down the ancestors of spirit beings but only of real persons. The Bible must mean to say that Jesus is a real person! Jesus was a real man on our real earth and not just a part of some spirit world; not just some of the white man's magic!"

Jesus is a real flesh and blood person. He identifies with sinful humanity by undergoing the same things that they need to undergo: Birth, death, and, here, the baptism of repentance for the forgiveness of sins.