In What Is It About Immersive 3D?, I claim that being immersed in among the application components allows and encourages us to mix and match among bits and pieces of different applications. That is, we’re getting rid of the idea of having separate “applications” on a computer.
I forgot to mention the other aspect of immersive 3d: that we want to get rid of the computer. Well, actually, that we want to make using each application object feel like a real world object, not a computer thingie. The direct manipulation feel makes it easier to work with stuff, and the lack of indirect abstractions and symbols makes it easier to understand.
A few examples below the fold.