The pros
With virtual reality, I have noticed that there are a lot of benefits when it is used with your students in a classroom. These benefits are also greatly increased when you are in a DL classroom. Virtual worlds allow you to create a space where you can build and insert content that you want to give to your students. It also allows everyone involved to have their own avatar and interact with each other in real time. Having a DL classroom where my students are all over the province and sometimes travelling and are all over the world, it would be a great way to still have a sense of community with everyone feeling connected.
The cons
The biggest issue that I have come across so far - and it is something that I personally experienced - simulator sickness. I honestly didn't think it existed until I was playing around in a virtual world and was looking through the eyes of my avatar (instead of being able to see my avatar) and then all of the sudden, my stomach turned and my head started to spin! This is something that I can now be aware of and know that some of my students may experience the same thing, although if something is making me feel really ill, I probably won't be using it with my students. I will look for something where I can comfortably immerse myself in for at least an hour without having to go have a lay down.
Considerations
Not all virtual worlds are the same, but neither are all textbooks or all chocolate chip cookies for that matter. You have to explore and find what works for you. You also have to be aware of all the ins and outs of a program before blindly giving it to your students to use. Something that is big right now is privacy, it always has been and always will be so knowing where the servers for the world are and what privacy laws they are under is something that you should know before introducing it to others.
In conclusion, find what works for you. Explore it. Learn all about it. After all that is done then share it with your students and see where they can take their learning using it!