You don't need to even go into sci-fi land to reach a dystopian scenario.
With no laws to govern what technology like this is allowed to do and what can be done with the information from it, Facebook and companies like it will be able to create products that do what the press release implies with VR, but since they'll then have a direct monitor on our brains, they'll eventually be able to measure response to advertising, gauge public opinion, tell when someone is lying, and even flag certain types of brain activity as "potentially dangerous" if it's determined that certain patterns precede violent actions like police being in a gun battle or a soldier being in combat (or even violent sports).
I hope they don't manage to develop a successful product that does this, but I also think enough corporations are working toward doing so that we'll have to deal with these problems in the next 1-2 decades.
