I haven’t found any reason to use the shotgun instead of a submachine gun or an assault rifle. I don’t know if anyone else uses that as their primary weapon or has found a reason to.
It has more stopping power but most zombies only take 1-3 pistol or machine gun shots to kill them anyway, so that isn’t really appealing since 95% of the time you are firing at regular infected and not special infected.
It has no ability to fire medium to long distances (which is important when you see a special infected, by the time you switch to the pistol they may have moved out of sight), and it takes longer to reload.
The only real benefit I can think of is using the auto shotgun against the tank when you are at close range. Aside from that it really has nothing to offer over the machine guns.
Yeah, the shotgun fell out of usefulness once the metagame shifted away from DPSing tanks to kiting tanks. One auto-shotgun is useful if your team only has one melee weapon, since it’s the best way to drop a charger after they grab your only melee or if you need to cr0wn a witch. The tier 1 shotgun is only useful for witches.
In the first game, before the first patch, the shotgun was probably the best weapon. After the first patch, the shotgun pellets didn’t carry through common infected, or not as much as it originally did. Before that patch, the hunting/sniper rifle didn’t go through common infected. After that, it went through a few of them.
The shotguns are the mobile, sustained fire weapons. The “longest reload time” is true if you’re running them empty, but the entire point of their reload mechanism is that you never need to do that. You can take brief intervals between shots to feed single shells in, giving you an optimized and consistent uptime/downtime ratio compared to the other weapons, which pairs nicely with its high damage per shot.
Accuracy is something of a red herring, btw. Shotguns in the source engine always fire a pellet down the center of aim on pulse fire, so you can headshot things perfectly well at any range. It’s not a strong headshot but it doesn’t need to be in L4D.
Personally, I’ll always take a shotgun over the uzi in t1 weapons. In t2 I tend to prefer a more deliberate playstyle, but the shotguns are still useful in several areas, especially in Versus where you tend to be moving more.
The shoguns are great in Scavenge where you always have access to more ammo.