Everything becomes possible. You can enjoy a universe as varied as dreams AND still share it with other people who are plugged into the equipment, instead of being trapped in your own head. To all those connected, a tree can suddenly transform into a sparkling waterfall. On the other hand, if reality is digital, everything is the same as everything else. In other societies, the phrase might merely suggest the degree to which multiple minds contain mutually coherent models of the world.
Metaphors are luxuriant, youthful, optimistic.
Every time we make a metaphor we are returning to the Eden of meaning, before meaning decayed into frayed words. The computer will probably be a part of the human environment for as long as people exist. At the present time, the culture of computing is dominated by greed, politics, and banal design. The Virtual Reality metaphor enjoys popularity because it leaps over the current bland mess and expresses what is fascinating, inspirational, and terrifying about computers. As long as it lives as a metaphor, instead of a term, it cannot be contained, boxed in, owned, or controlled.