SUL has its place, as an "easy button" to quickly teach folks how to move around each other safely in a cramped environment. I have taught this to others for this reason.
It is NOT the awesome, universal technique some make it out to be.
The position he's advocating has merit, and I may explore it and put it in the "toolbox" at some point, but it makes it awfully easy to muzzle your hand under stress, I think, without a huge amount of muscle-memory ingraining.