You might be under a misconception here. The workout is happening with the real body in the real world. "VR" is just a medium of choice for extra fun and motivation, like playing a game.
The outside view of VR workouts is usually the "play a game, workout by accident" appeal.
Although I believe it's usually the other way around. People play games where they are moving quite a lot and afterwards realize that they are actual getting exhausted.
And then they realize that they didn't really notice that exhaustion while doing the actual movement ( focus on the game, outside world mostly blocked off ) so the thinking is "wow I can do workouts without having to dread them and without being pulled away by other distractions, and all that from my living room"
There are already studies that show people feel less exhaustion while doing a VR Workout compared to a classic workout when done at the same intensity
The "real world" isn't very real either. It's all built environment, contrived. Even the countryside is largely man-made (farms, roads, paths, save for the occasional old growth forest).