Snip
I think he is hot melting a straight edge on to the rough edged stock and runs the straight edge along the TS fence. With this type application or a sled like I use it takes "1" pass on the TS to straighten the most crooked of edges. With a jointer that takes several passes. Think about taperng a leg, you can do that on a jointer with several passes or with 1 pass using a taper jig on the TS. The jig the TS workes much like a taper jig, it uses a straight edge to reference the TS fence.