This hints that people are a little more than friends. The act of playing fortnite together, a deeply embarrassing game, shows the true passion between people. It shows the connection and vulnerability between a couple. This presents them being more than friends but not ready to share it.
Person1:Hey, I need to take a shit Person1:Oh yeah, i can just sing the fortnite battle pass song while im about to drop a hiroshima in my own house while my kids are in my basement.