I imagine it is popular because it feels relevant. Like the article said, the goal is disassociation to cope with the experience of war. If you are all engrossed in a game about virtual tanks, I imagine that makes it feel more like a game when you are on a real battlefield with real tanks.

One ukrainian military psychologist and youtuber I've watched, Філософ Рептилоїд, frequently said how him bringing a laptop with games to a barrack set up a better overall atmosphere in a combat unit. Gaming is intense and occupying enough activity to distract one from fatigue of the battlefield for a couple of hours. Guess, even wargames work.