Actually using these in theses side articles in the WT and Awake in the instruction talk started in 1999. Most JWs don't read those articles (especially the elders) and many of those articles address specific behavior and thinking errors in the congregation. Before that the Proclaimers book was used, also a book not many read. I guess the GB is assuming they will make you hear it if you won't read it. The Insight Book was covered in the other talks #3 and #4, covering persons mentioned in the Bible with a fairly substantial section.