And yes, it might target suboptimal points. A good player can do better barrages into the FOV. But the issue is that CB leads to having literally zero downtime. Even a good player will forget to use the barrage ability for some time after it becomes available again. CB will fire without fail, because in team games there are 1-2 barrages per minute somewhere on the map. And while there might be differences at the very top tier level, CB level the skill gap between "bad" and "average" players, simply because micro and game knowledge are limited resources here. 5 okay barrages are as good as 4 good ones, especially if I don't need to think about this unit anymore.
I use lefhs fairly often and I've had good players adjust to my cb and barrage right outside of it's range. It can also be left on cb to waste if this isn't caught