One problem surgeons struggle with is control of the condyle within the fossa. If malpositioned, then you end up with joint problems, not good for business. The larger the movement the greater the problems. Only a surgeon could comment on the significance of the new cut of course but qualitatively, it reportedly reduces these problems. As for the notch, with large movements, especially above 7mm, there's often a "notch" that appears in the jaw line. That notch is quite common already in fact in people with facial deformity. I never noticed before but feeling around I have it too soft tissue just masks it well. As you get older it can show with soft tissue changes. I've seen the plate on imaging, it's really small, which is a nice bonus. The NSD bonus is also quite amazing.
It seems like a huge deal for people needing large advancements. That being said, if I asked a reputable surgeon about it and they said they were familiar and weren't impressed, I'd probably go with their recommendation. I try to encourage people not to diagnose themselves but rather focus on finding people with the right knowledge base and then going with their recommendations. I try, I'm guilty too