What works 'here' often does not work 'there'.
So I'm sure what works 'there' shouldn't be criticized from 'here'.
With farming a few decades, and caring for soil a lot, and experimenting with different things to keep a healthy soil 'here'....
I have way more questions than I have good feelings about that video.
To say the first year might be a tad less productive do to lack of nitrogen is perhaps some wishful thinking. To say the ground will be barren until a lot of that wood rots might be more accurate.
Even hardwoods give off toxins, depending on the species. Can really hamper some types of garden plants.
Why does one build a raised garden anyhow? Of course they will dry out if they are hills built that high. Wouldn't level or alomst depressed conserve the water? I think in 4 decades we've watered the garden 10 times or so - just not a common thing to do.
Sure couldn't get many root crops from such steep ground, with such a shalloe coat of dirt over the wood.
For me, that appears to be some book reading, applied in ways that are designed to fail - anyhow 'here'.
I'm sure things can be learned from it, and perhaps it's perfect for 'there'. I just can't imagine gaining anything, but creating difficult growing conditions and reduced yield 'here'.
I'm only commenting because it's interesting to me. Don't mean to be the wet blanket I sound like...

I just miss the point of it from start to finish. Build a hill to save water???? Make shallow soil with rotting, sinking wood in it so it's not a stable root bed? Attract insects? Make stee sides so what rain comes will wash off quick?
I'd have ot see more of what good it offers I guess. Not thinking of much?
--->Paul