TomD
While SD is dead on, they are used by some people mostly to reduce tear out. One example of this is building Osage bows. Osage is a wood that can really pop chunks. And to make matters worse, bows need to be perfect. Not only look good, but as the saying goes, "a bow drawn is 7/8 broken", so any error in the grain equals a broken bow. Other than sidecut, there can not be any grain run-out in a bow at all. So popping chunks is going to cost you. In most cases they are probably planing materials to prep for lamination, so in that case you have the dual benefit of not tear out, and a prepped glue surface.

I guess it works because the shaving has very little integrity. The shaving looks like excelsior. It would be very difficult to get the plane perfectly lined up with the grain, and any cutting across the grain will result in very short chip segments. Kinda like sanding vs planing.

Whether this is just the influence of bow maker Dean Torges, a very able woodworker, I don't know. Could all these woods be just as easily planed using higher end techniques, maybe. But for the case in point there might be little advantage.

I have seen the same thing with musical instrument makers.