I just think, because Chuckie is actually breaking the forth wall by looking at the screen when his eyes glow, because he looked at the screen i see it as being intended for the gamer, guybrush didnt see chuckies eyes glow so i dont think it is him still imagining.
Well i don't know it this theory is right or not, and i don't care so much, but still.
Yeah, these are mostly nods to the player, but they can pretty well be there just to tell you that guybrush hasn't quite stopped daydreaming yet.
After all, the player is supposed to kind of "be" guybrush when playing the game. So it could still be a way to tell you there's still stuff going on in his/your head.