I think he's doing it because he can. Other than time, it costs next to nothing. It will lighten the rod a bit but not really enough to make a horsepower difference. It's like removing casting flash on the block, it's supposed to make the metal stronger but when was the last time you saw a Mopar rod break especially along the middle.
You'd see magazine articles back in the 80's about doing rods like that, they seemed paranoid about the short block coming apart, it would be a 325 hp build and they would need a steel crank 4 bolt main rod work like that etc..