A possible error but a lot of confusion


I refer to the tutorial by Karan Shah “Marking the Seams and Unwrapping the Model” which is pt 2 of his excellent Creating a Low Poly Medieval House in Blender:.In step 5 he writes “Switch back to Edge-select mode. Hold Shift and then right-click on the side edges of the house as shown in the image. Press Ctrl-E and click on mark seams.” But in the accompanying image he only shows one edge marked. He then in steps 6-9, goes onto the unwrap where he describes how to juggle the result so it looks neater in the UV editor. So far so good.
But wait, Jump to step 10 and the images there show that his building has now 3 extra seams on the remaining edges!!! And you would not get the same result if you unwrapped this with the extra edges. I was very confused by what he was trying to do. If he was trying to demonstrate how to juggle your unwrap on the UV map then fine it succeeds, but it does not say that in the body text. But it does leave me wondering should I keep the unwrap and juggled layout from steps 5 - 9 OR should we ditch that work and go for the illustration of the building in step 10 with ALL four corners ? Can this be made a little clearer please?