One of the benefits of the AR platform is parts availability and interchangeability. For many that is the appeal of the .300 BO. Literally, all you need is a a different barrel and different ammo.
To say the 6.8 or the .300 has better ballistics than the other ignores many aspects of ballistics. Either is suitalbe for the intended purpose of hog hunting. When you factor in the probable distances, energy, blood trail, etc. you are probably at a wash at best, but in my experience, I would go larger diameter over more speed inside of 300 yards.
When you look at ammo cost and bullet selection, then of course, the 300 BO holds an edge.
Skip all that and just get a .450 BM.