I'm a longtime subscriber to Dave's channels going way back to before he was on TV. His focus has always been low cost "common man" self reliance and survival skills.
I was eager to watch that video last night when it appeared in my inbox.
I had the same concerns about the rope and the s hook that you did but I was not too worried about it. Dave never presents things as the only way to do it and he often mentions how viewers respond and provide him with more information in the viewer comments section. Once I got past the point that my hero was not using amsteel whoopies and tree straps (grin), I found myself admiring the simplicity of the slip knot/stopper knot idea. I am especially interested in how it could potentially replace or be used instead of a marlin spike hitch.
I am going to experiment with the idea using my tree straps and a carabiner or a descender ring to provide the interface link between the slip knot and my amsteel.
I watched the video shortly after it was posted and users had already commented on possible condensation issues from using reflectix and a pad as insulation under a sleeping bag. Dave's reply was that it had not caused him problems when he used it.
All in all, not a bad quick tip from The Man! lol
Here is the video