I view it as simply organized combat vs personal combat. You had better get the upper hand ASAP and destroy your opponent or drive him off the field. The ROE are different in the personal variety because after the rout, you can't run him down and kill him.
“Nine-tenths of tactics are certain, and taught in books: but the irrational tenth is like the kingfisher flashing across the pool, and that is the test of generals. It can only be ensured by instinct, sharpened by thought practicing the stroke so often that at the crisis it is as natural as a reflex.” ~ T. E. Lawrence