Well their saying this mode is like PUBG. And it is. Fortnite Devs themselves advertised as being of the same vein. And yes its not the first but it is by far the biggest and has the most visibility. Most people know what it is as soon as you say PUBG. Like when people would a game is a cover shooter like gears of war. They aren't saying gears of war was the first but it was the most easily recognizable for people to grasp.