It even says so below! I simply cannot believe how people do not understand this??
"Tripple buffering is recommended for the smoothest experience" Smooth = good. There you have it.
More detailed explanation below...

Vsync can invoke triple buffering which can "improve" frame rate while at the same time increasing input lag, sometimes severely.

It's typically recommended that you run with it disabled, HOWEVER if your experience is overall better with vsync, then it's down to personal preferrences. A lot of players dislike the tearing and rapid climb/cratering of frame rates while gaming and vsync will tend to take care of that, but it can also cause some other unintended issues too, as i said, test it out and see what you find.
Many people are now focusing on using freesync options since they have all the benefits of v-sync and none of the cons... in fact it actually improves significantly on it as input lag is definitely eliminated and on AMD graphics cards, using Chill with overwatch reduces the input lag potentially further while lowering frame rates when it's not required, the result of which is basically the equivalent of running 300fps all the time (pros usually always want ultra high frame rates WELL beyond their displays capabilities to ensure the lowest input lag possible, radeon chill takes care of that making even a lower end graphics card capable of producing the same level of input lag or at least very close to the same level).

As for the purpose of V-sync.. it's designed to match your monitors refresh rate (how many times it draws the image on your display typically top down) in order to give a seamless smooth video output free of artifacts and other associated potential issues. It will attempt to lock in the frame rate preventing a graphics card from working beyond what is necessary and also will drop the frame rate to the next viable option if the maximum your monitor can support is not obtainable at the moment.

This is very simple if you do not understand this you should stop reading at this point and take a break !!

So obvious tbh. If yuor mouse accelerates u get faster to the enemies head whats so hard ot understand there?!?!

Mouse acceleration wasn't created for scrubs, just chosen player usage. The idea is that if mouse sensitivity is low, it allows for better precision, but then to get your mouse cursor across the screen you have to drag the mouse across the pad, lift and move it back, drag again, repeat. If sensitivity is high, you can get your mouse cursor anywhere on the screen without lifting it off the mouse pad, but then it might be hard to get the cursor exactly where you want it to be if you have to click a small button or highlight a single word in a document or something like that.
Mouse acceleration attempts to fix this dilemma by dynamically adjusting the sensitivity based on how fast you're moving the mouse. The idea being that if you're moving it slowly, you're probably trying to make a small, precise movement, but if you move it quickly you're getting the cursor from one side of the screen to the other.

there u ned too set it to as far right as u can possibly can thjat way ppl will have a very hard time to see u its only recommended for assassin players in this

if u have a higher resolutioin you see much much more enemies this has been proven by scientists long ago and if u want to shote more accutarely you need a monitor with higher resoluition.
if u are rich enough mb also buy with 120+ hz

!!!! ONLY DO THIS IF YOU CANNOT AFFORD A 2K or a 4K MONITOR !!!!

if u do this u will be able to see enemies MUCH more clearer and you wont have a hard time hitting them because you see them RIGHT AWAY !!