There is tremendous potential for this technology far beyond entertainment. It allows the user to perceive themselves to be in another place with minimal need for imagination, abstraction or suspension of disbelief. Those qualities all lend themselves quite well to entertainment, but they also enable many uses as a tool, such as for industry or education. Zuckerberg is counting on this, though I suspect he is thinking along the lines of the social implications (a family on different continents could sit down and have dinner together, or you could play a card game with your grandmother from 1,000 miles away).

VR enables the use of human-operated tools and machines in places we cannot physically be with a minimum of interface limitations. Consider robotic surgery; the current Da Vinci machine uses a 3D view-port at a large station with three small loops to detect the movement of three fingers on each hand. The upshot is that a surgeon can now see a 3D view inside an abdomen and manipulate surgical tools with almost the full amount of dexterity of a human hand. This differs notably from older surgery methods in that only very small incisions are made to access the abdomen rather than a single very large one, greatly reducing the pain, scarring, and risks of the recovery process (though of course laparoscopy also offers similar benefits, save for the tools' degrees of freedom). VR is close to replicating this with much less expensive technology in essentially any environment you could choose, provided latency is kept low. Soon a surgeon could be in a separate, non-sterile room with a VR headset on and manual controls to enable full hand and wrist movement, and software can intervene with safety measures to prevent sudden unintended movements or accidental damage to important structures like blood vessels or nerves. The scale can be altered so that the body is perceived to be the size of a room and tools can be manipulated on a finer scale than the human hand is capable of (think of performing surgery inside a blood vessel as if you were there, rather than manipulating primitive instruments at the end of a single camera on a catheter as they do now).

We could teach physics in a digital space where you can alter physical constants to gain an intuitive sense of their consequences. We could teach geography as if we were flying over any place on earth. We could reconstruct New York City circa 1900 and walk its streets. Walk the ocean floor and collect samples for scientific study. Defuse a bomb from a mile away as if we were standing in front of it. Clean a nuclear waste zone with no radiation risk. See the full scale of the earth as viewed from the ISS or the moon. Conduct rescue efforts in burning or damaged buildings with no risk to the rescue crew.

A lot of these things are already possible, but VR dramatically reduces the level of training needed to adapt to unintuitive user interfaces. And there will be many applications no one has thought of yet. A few days ago I saw a video on YouTube where a Disney artist talked about how Tilt Brush fundamentally alters drawing in a way that has never been possible before. Sculpture is about subtracting or manipulating something already existing to create art, whereas painting generates something wholly new but only in two dimensions. With Tilt Brush be recreated Ariel and met her as he sees her in his mind for the first time - a three dimensional entity taken directly from his mind with none of the limitations of sculpture and all the freedom of painting.

As with most technologies, entertainment will probably drive the initial development of the technology. And I do expect it to be successful - I've demoed the Vive and it does not feel like a flash in the pan the way previous attempts at VR have (here's looking at you, VirtualBoy). The software will need to be there to drive the market, and growth will be slow in the beginning due to cost considerations. But people also said home video with the VCR was a flash in the pan and it was too expensive to ever be successful, people would always rather go to the movies instead. VR represents at least as much of a shift in culture and technology as home video did, probably much, much more. I'm looking forward to watching it happen.