I'm the center of the universe. Aren't you?
Most people who works on games have a self-centered view. The lead artist figures the player cares the most about character designs and expansive vistas. The composer knows that players are moved first and foremost by the swell of the opening music. The multiplayer designer is certain that players couldn't care less about campaigns, and only notice well-balanced PvP.
They're all partly right. EVERYTHING makes up the player's experience. And the player's experience is everything. We know from our work in games that a player experiences "performance" from the first website visit, through the download, to the matchmaking, update and community engagement. Any snags and players leave. Performance isn't just a list of specs; hardware capabilities and frames per second. It's also not just the story, or the compulsion loops.
We see performance pop up at every technical step of the player's journey. Every glitch, and every wait becomes a part of the player's impression of the game. We've studied player behavior and confirmed this. We've asked industry experts and they've corroborated this. They even said it on video!