This is one of the single most unrealistic and dumb additions to practically every single first person/over the shoulder shooter (even fucking MINECRAFT) EVER created EVER.
There is NO POINT. It's turbo unrealism at it's finest.
Do any of you people on this forum walk around like your head is on a chicken neck, rolling and wobbling all the goddamn over everywhere on a freshly greased ball bearing- doing that black girl "nuh-UH MHmm gurl" neck thing?
NO!!!!!!! NOBODY FUCKING DOES THAT.
Especially not while toting around a weapon that you would be 100% more likely to shoot yourself with the wet end of it if you DID walk around like that.
Head bob is EXCRUCIATING. Especially in games such as DayZ, Rust and Sir, You are Being Hunted. Where you need to be aware of your surroundings at all times- but when running suddenly EVERYTHING IS MOVING in your peripheral vision, making it impossible to tell if you are aware of the dangers around you. Luckily, there's people who get motion sickness from this kind of movement so a lot of games have a toggle for it. (But not all of them.)
Not Being Able To Look Down
I get it, lots of games only let you look down to about 300° from 0 on the Y axis, this is done so you can't see your "missing legs and wedding tackle". Okay, sure that's great, if there's another perspective, like third person, or cinematic views that you CAN see your "feet"[read legs] in.
This is especially frustrating in games where you also cannot look UP beyond say 65° from 0y. Yet there's things you need to shoot/look at in the air. And suddenly to shoot things above you have to run backwards for days or level yourself out with them like some kind of idiot who somehow stopped understanding how to shoot a gun at things.