The killer app for virtual reality is AI able to act like and interact with humans.
There's a strong Oculus-in-Second-Life effort, because it's the only non-game, non-trivial virtual world left. Virtual worlds keep dying because there's no killer app for them, yet. Creative people build pretty spaces in virtual worlds, but nobody will visit because they aren't engaging enough. It's not enough to have things to look at.
People are more interesting than things. Virtual worlds won't be engaging until there are a lot of people there. They won't have a lot of people until they are engaging. Chicken. Egg.
To make matters worse, virtual worlds tend to become larger than is useful. Too much space, too few people. They become ghost towns. Creepy, empty and lonely.
The solution is AI. Fill those spaces with AI people, or monsters, or whatever, and they'll be much more interesting. Visuals aren't enough, though. You have to be able to interact with the AI.
The challenge is that virtual spaces will become so large you won't be able to find real humans. You can reserve spaces for real humans, but if you got there through first making virtual spaces attractive with AI, then that AI will be used to fake humans in human spaces. Second Life already has this problem, though the AI is nearly non-existent. SL seems empty and creepy, despite being full of avatars, because most of the avatars are bots.
But if you can have an engaging time in a virtual world, interacting with bots, will you care that they are bots? The time will come when the people with the best stories and the best jokes and the best advice will be AI.