That is a surprising thing to note. Though it does help set up two of the most important scenes in the movie: Lightsabers are used in the dramatic battle betw

That is a surprising thing to note. Though it does help set up two of the most important scenes in the movie: Lightsabers are used in the dramatic battle between Vader and Obi-Wan; It's good to have them in a few scenes if the first time they're in a battle, the mentor is killed. Furthermore, at the end when Luke is doing the trench run, he's relying on his targeting computer until force ghost Obi-Wan tells him to use the force. This relaxing and trusting in the force was directly set up in the Falcon training scene. I think overall this is the best way to use Chekhov's Gun: Introduce several things, but don't make it obvious how they're going to fit together.