The whole of the Bible is useful for doctrine, reproof, and so forth. Sometimes, when read a genealogy we can become bored, because its value is not immediately apparent. One use for these genealogies is responding to groups who make false historical claims. I recently have been using them in response to Harold Camping. However, in the video at the following link, the historical evidence about the date of the destruction of Jerusalem is used in a similar manner to undermine the Jehovah's Witnesses (link).
JWs date the destruction of the temple at 607 B.C. Modern historians place the date around 586-587 B.C., whereas Ussher places the date at 588 B.C. (link). This difference may seem trivial, but - as the author of the video points out - that date turns out to be key to the calculation of 1914 that is used by JW's to establish their authority. If that date is not right, then the rest of the system collapses like dominoes.
The same, incidentally, is the case for Camping's system. If his date of the flood is wrong (and it is) then all the dates he's been setting are wrong, and his claim to have special insight into the text of Scripture is also wrong.