To really explore virtual worlds would take lots of time. I'd like one of the Time-Turners that Hermione had in HP3. Experiencing second life would put a big dent in my first life - not at this time, thanks.
I can see that there is great potential for educational use of virtual reality, but I think lots of PD for teachers would be in order.
Perhaps in the not too far distant future, web users will naturally expect web pages to be in 3D, just as we expect films to be in colour, not b & w, or print texts such as books to be more visually engaging than they were some years ago. Does it enhance the users' experience? Perhaps it depends on the desired outcome.
Online games are popular with lots of people and will no doubt continue to develop to new levels of technological sophistication which gamers will come to expect.