Despite almost two years of addiction, I'm a lousy shot over long distances, especially against moving targets. Full auto allows me to compensate by "walking" the fire into the target. On short distances, I have bad reflexes and bad aim, so the ability to just pump the entire room/corridor/trench full of lead without the need to aim is essential. Failing that, I will use area effect weapons such riflenades, hand grenades, and PIAT, or in close quarters, the melee weapon.
However, on medium ranges the bolt action is the king. Bolt-action rifles generally have better sights than the semi-auto rifles, and are 1s1k (unlike M1 carbine and StG44).