Right now they allow for 1000 yards plinking. Lose this and you will reduce sniper shots at these ranges.
They show through the instrument panel. Lose this and dogfights will have less gamey taste.
Even .303 creates a hit sprite as 75mm of Panzer HE shell. Do you really think you could see a .303 hit at 700 yds at a metal surface ?
It is a small thing, but would have great impact on gameplay.