Those are very cool, I am actually planning one for under our deck soon. We have a walk out basement and the last retaining wall was
wood which has rotted and disintegrated. I'm intrigued by the lower need for building skills, the longevity, permeability and the ability to add soil to the top and plant. The area gets a lot of southern exposure and I'm thinking of using the top of the gabion for winter/early growing with the benefit of the thermal mass from the stones. It seems so much more dynamic than a regular wood or brick retaining wall.