Put very simply, a virtual lab is a place where trainees can learn something without altering the entire ecosystem of that field, like practicing a new software without the outputs of the practice affecting the entire internet, or more realistically, the organization.
The trainees can tinker with the equipment which simulates the environment in general and perform experiments that yield authentic results too. Though the results can be used in the longer run for actual processes, they are not yet completely ready and usable.
A virtual lab is different from the generic perception of a LAB – these are not restricted to just science experiments but can help programmers learn and understand code. The biggest advantage of a virtual lab is that it is almost impossible to damage self or break equipment or affect the study environment negatively even if there is a big mistake. Another advantage is that you can perform studies and conduct experiments in a virtual lab which are not feasible in the real labs.
The simulation development for a virtual lab takes time, but the learning advantages are quite astonishing, especially in these times when stepping out into the open is risky. With a virtual lab, you need not compromise on the learning.