Once the structure has collapsed, you will have a beautiful mound to start a 3 Sisters planting.
(Or a wheel barrow full of great
compost to use elsewhere.)
I like it as a great way to utilize limited space.
If you add a few each year, by the time you get back to where you started, your
yard will be knee deep in beautiful tilth.
I think that I may use that idea (even where space is not a problem.
It will create pockets of abundance.
The one in the bottom image that is made from planks
versus logs is a great example for those people who have access to
pallets, but not logs (or whose logs are all destined for the
wood stove). I could imagine that built in a triangle, with one point facing due north. One side would capture the morning sun, one the afternoon sun, while the third leg took the full brunt of noon day sun. Depending on one's climate, each side could be planted to maximize the habits of the plants selected.