They did discuss the case of an alarm becoming more insistent if a pilot didn't notice it. I think it's a small hop from that to "We will only charge you for the ads that people notice in our ad supported VR game" type stuff.

I assume you could also use this for ad targeting if you could get people to watch the right content with their brain reading VR helmets on. "This person focused a bit more on the Cadillac driving through the screen than is typical. Let's show them a Cadillac ad."