Back in like 1996 when I was in the army in Fort Irwin, CA, I was the 'Regimental Automation Officer' as an E4. This game me certain privileges.
One of those was the ability to put coax capable outside the barracks, which was run to a dozen rooms to create a network. See, in the barracks in the army, you are put in a room with 1 or more of your squad mates, and you are all, whoever is single, are basically in 1 long hallway.
So, we'd all open our doors and play duke nukem 3d together. We were all squad mates, we knew how to move, how to fight, how to stack and clear rooms, blah blah. What happened though was some of the best training possible. We knew everything about how we all fought. It was amazing.
If you have never played a shooter like Call of Duty or War Thunder or, well, any thing kinda realistic like that, with your own military buddies you train and live with, you will never understand just how truly different those games can be. I have no doubt that if there were infantry squads working together in COD (I'm not sure if the new one supports 9 or 18 players playing together on a team without randomization) they would flat out dominate every match they are in.
Course, there is still some "gamy" aspects to these games, but trained soldiers working together in a tactical situation is crazy effective vs just everybody doing their own thing.