We added one on our home built mill. It's only useful if sawing alone. We tried to never do that. It's currently bungied up out of the way.
We used several sets of rolls, to be able to shove lumber-slabs- cants-table slabs, out of the way, to different areas, as we sawed.
Never leave home without rolls. They are the 2 black "legs' attached directly under the engine.