I first knew about this notion in this video(in Traditional Chinese) talking about the philosophy of Virtual Reality and VR movies.
The French philosopher Gilles Deleuze stated that both actual and virtual are fully real. While the former has a concrete existence, the latter does not, but it is no less real for that fact. Like some conceptual inventions which people pursue such as freedom, equality, justice, we won't say these aren't real just because these are virtual or these haven't been realized.
This distinction is initially treated as an esoteric interest only to specialists in the field of ontology. However, since the advent of computer games, or more especially now we have Virtual Reality technology, this distinction has become more essential it reminds us that what is seen or experienced on screen is still real, even if it is not actual.