Luxury or necessity?
So, why do you need a mark, because you probably already see these stern guys on the merging background. No way!
Even if you have 4060 rtx and other top-end hardware - this does not mean that everyone sees a dangerous enemy, this does not mean that you do not need to mark the enemy!
Players may simply not notice the danger due to the fact that the enemy merges with the background!
It's sad that such a simple action needs to be explained in detail.

Just when you see an enemy, press the button that is linked in your settings (in the Russian version of the game, the default button is T(e) (Russian e), in English versions, this button is often Q(й), for convenience, I recommend changing it to the letter T in the settings)

This is necessary primarily for the convenience of the player and his team.

Often special opponents stand behind a corner or obstacle (or just jump out of nowhere), and the player walking ahead may not notice the danger!


This helps you prepare in advance for a fight with a strong or dangerous opponent!



It also helps your teammates a lot and makes their job easier, especially against ranged opponents!



Also against dangerous special opponents and bosses!



Also, a mark is necessary to mark items/first aid kits/medical stations!



Marking in battle will not take much time, it will not distract you from the battle, it is not an unnecessary action or a waste of time (it can be freely done during battles or while standing in a block!), thanks to the mark, your ally can literally destroy the danger in a couple of seconds!




It's trivial that melee players might not notice the danger and not have time to react to it!




(second screenshot - explosion of the demolition man, despite his beeping and screaming - the bb (close combat) player did not hear or see him, because he was unmarked and paid with his HP, and at high difficulty levels such mistakes are critical!)

***When you fell or were caught by the trapper, you can also mark the enemy!
So far relevant as of 02/18/2023*

A special honor was given to the new game class (it seems to me that the developers themselves are already trying to force players to mark). The Arbitrator with a dog has a "target capture"/"attack command" mechanic, which is activated by double-clicking the "mark" button, which allows the hound to immediately proceed to attack the target you marked.



Attacks of your faithful dog, by double pressing the "mark" button gives the command to your dog to attack the target, thus your dog will pin the special enemy to the ground.



This allows you to get close to the enemy and finish him off manually or finish him off with a ranged weapon.





Targets such as enemy hound, blaster, ogryns, runner - when double-clicked, the dog begins to stop and stun the enemy you marked by giving the command to attack by double-clicking the "mark" button on the arbitrator.




Now the mark is also important for playing on the arbites, this is an incredibly useful mechanic for controlling an enemy that you can't reach or don't have time to shoot at (for example, when a close fight has started and the sniper is shooting from afar. You can simply make a double-mark command for the dog and in the near future the good boy will bite the hated sniper to death!)

So, we figured out why a mark is needed and how important it is, not only for yourself, but also for your team!
Remember that you are playing with a team and such a small and simple, but important action can save you, your comrades and improve team play!
A mark in battle can prevent the loss of a comrade!

Good luck to you and victories in the game!
DON'T FORGET TO TAG YOUR ENEMY!