Week 3 in the NFL is an interesting week, because it is the first week after which the first teams are basically eliminated from playoff contention. Since realignment in 2002, only one of the 81 teams that started the season 0-3 made the playoffs, which effectively means the 0-3 teams (Redskins, Dolphins, Jets, Steelers, Bengals, Broncos) can all start focusing on mock drafts.
Week 3 is also interesting for the seven teams (including the Cowboys) that started the season 3-0, because those teams are already on a playoff track, as their historic playoff odds are already quite high at 70%.