That, and a whole lot of other things.

Imagine any game where you've got an assistant/sidekick... Say, a fairy companion that not only says, "Listen!" Every now and again to point out hidden things nearby, but also occasionally makes fun of you when you miss an easy shot. Or reminds you that you really shouldn't have accepted this side quest if you were going to take THREE FRIGGIN WEEKS to finish it.

The possibilities are endless!

What I would do would make a game sidekick that had a constant fear that they were in a simulation and would try to break through the 4th wall when it (the game) hears (via your PC's microphone) people talking in the background through "your voice". Or when it hears your phone ring or message tones, etc. Because that would be so immersive and also hilarious!