As far as copying what brewies do in most cases I would suspect they represent a best practices. As a homebrewer we need to decide if something is worth adapting. Normally complex procedures with expensive equipment for an efficiency gain is not worth the cost/effort so we just use a little more grain. I may also question why homebrewers use a grain mill when a rolling pin would also crack the grain and the poor efficiency from that can just be make up by using more poorly milled grain? The answer is a mill is reasonably priced and easy to use.
the easy to use is a REALLY big part. I can't imagine trying to crack 20lbs of grain with a rolling pin. even with a mill it takes 5 minutes or so and that's with a drill on pretty much full throttle.