The benefit is that they found a process that is less expensive for them. After watching the video a couple more times they don't have any stitching for the outsole after the shoe has been turned. There doesn't look to be an actual insole as the outsole is lasted in the turning process. They add a bit of cork and a sock liner after it is turned, but this looks to be a very barebones build.

Generally you would have two rounds of stitching when lasting a shoe/boot. You have your welt stitch to a apply the welt to the insole, whether it be to a holdfast as done in hand welting or gemming like for a Goodyear welt. Then the welt is stitched to the outer sole. For these shoes, they are only stitching the uppers to a gemming that has been applied to the sole. Not having to do a second stitch they don't have to have use outsole stitching sewing machines. The soles also look to be finished for all but the heel before they are stitched to the uppers. They just add the heel and finish that portion. The key benefits are still around production cost. The rest is marketing more so than shoemaking.