What thye mean by this is that if you were to arc your shots using a normal paintball gun you could potentially shoot as far as a flatline. But this is impractical for woodsballers because you would hit a branches if you arched your shot. The flatline isnt mean to give a ton of extra distance  because like everyone else stated balls would just bounce. So think of it this way instead. If your a speedballer youll know that you have to put arc on your balls flight path( tilt te barrel upwards) to hit the other side of the field. Well with a flatline you could just shoot straight. Both balls go the same distance, lose the same speed in flight, but the flatlines ball is going straight.

So for those people who are trying to be snipers and shoot people at long ranges with there flatline its a waste cause the ball will bounce. But for those people who play in heavily wooded areas and need to shoot straight thats where the flatline is especially useful.

At the field I play at 280fps is max, and useally I run from upper 260's to mid 270's (thank you palmer stabilizer) anyways, I still arc in the long ball and if you twist your gun to the left or right the shot will curve like a slice or hook shot in golf, perfect for getting people hiding behind trees not much larger in diameter than them.

If you play woods you want the flatline.