Yeah, the idea was more "imagination, romantism, illusion" are one side of the thing, the "creative" way of seeing thing ; that's where I'd put "immersion" because immersion is something you feel, like love or despair, with your emotions.
Typical example are Box Office action movies. Realist ? Really not, I mean flying people defying gravity and throwing fireballs at each other... Starfighters behaving like WW2 warbirds... That's not reality. But visually attractive, very entertaining, and simply put "fun" ? Immersive ? Yes indeed, it works because at some point you put a part of yourself in the characters shoes. The ancient Greek tragedies or the even more ancient traditional live artforms you have in Asia all work on that idea : you invest that emotive part of yourself into the play. That's what I call immersion. In those antique plays everything about human feelings and passion is a lot exagerated, and Hollywood action movies took that to another level thanks to technology. Next step ? VR, and a VR that will be more "V" than "R". If we have the opportunity to start another life in a virtual world, do we want to be subject to the same (boring) laws of physics ? Clearly no. We want superpowers, nothing less, we want to be the overlords in our own universes.
On the other side you have "logic, math, science" much more rationalist way of seeing things, all about depicting things in form of theorems and figures. Very accurate but often not very funny. But that's the only reliable way we have to build knowledge that describes the Universe in which we live. You can add religion there, in the end it doesn't change the big picture, still you have a way to explain the Universe, that's good as long as you manage the science-religion relationship, that can be even be something personal (as long as you don't publicly throw "You're wrong I'm right, the Earth shall be Flat !!" at Newton's face, very fine, it works). That where I'd put realism.
And Orbiter is designed in such a way you can really strip the whole Graphic Client thing and decide to make a "command-line engine". Realism will still be as good, it might even be more accurate because your FPS count is going to be insane, which opens the possibility of creating very complex interactions. I think this is the kind of sim they have in universities or laboratories : they enter command-line parameters or use a very basic UI for that and monitor the flow of output values. Immersion will be... not so good.
"Simulators", in the context of videogaming world, are caught right in-between, and that's a delicate situation. Say this is a big Windows GUI slider between "Art" and "Science". If you and I decide to start a new space sim (as a commercial project) and look for a dev team we need as much artists, for everything from 3D models to textures to cool landscapes ideas and inspiring background, than coders and "good-at-maths" people that will crunch as much real-life data as possible into our sim.
I'd say Orbiter stays more on the science side (Doc. Martin Schweiger is a real life scientist), something like KSP leans a bit more on the art side (it allows so much creativity) while still simulating a lot of "general physics" (and was very successful doing so, also made possible by the Unity game engine package that was a new thing). Maybe one day we'll have the best of both worlds but I'm not so sure, because... people really are more likely to use their free time with action movies than with maths problems. The users of this forum myself included being probably quite an unique species ?