I'm not sure that's true, especially if visual cues are how information is given. In film, this almost always requires that a character is our entrenched POV (ie what we the audience have been seeing is a delusion or something).
But a novel can spend the whole time talking about a character navigating a wilderness, sleeping under trees, listening to the animals in the woods, crossing mountains, etc. And then at the end, the withheld information that the trees are purple and the animals have five legs and three eyes finally reveals to us that this is an alien planet. The misdirection exists entirely in the mind of the viewer, and not a character inside the story. Our brains automatically fill in the gaps (the narrator says "tree" and we make a picture of a tree), and this is exploited by the author.
With a film, there are really only two choices when we are actually shown something. Either it's "real" or somehow it's unreal (a dream, a delusion, etc). Novels can withhold information (like the color of a tree, or the gender of the narrator) far more easily. If a film didn't show us our lead character's face for the whole film, we'd have a lot of questions and be very suspicious. An author can withhold basic "visual" information for almost the entire book if they want.
Yes, fair enough, I do see that, especially with regards to withholding visual information, film being by definition more reliant on visuals. (Have you actually seen
Malignant? I’m not recommending the thing itself, but I’m not sure it quite conforms to your “real/unreal”dichotomy, because it’s both). I guess to me there’s only so much “withholding” that can be done before it becomes cheating the reader, so I’m not in itself attached to that aspect of the reading medium - though it can be useful. I would interpret the alien planet situation more as cheating the reader than as an interesting use of POV. I think to me the rule of thumb is, if a fact is integral for me to understand the plot (and I’d argue the alien planet bit is), why is it being withheld - is it because the writer can’t naturally build up suspense without such tricks? Your significant other’s name example is spot-on, though. I was reading an article in The Times a few days ago about the discussions around adding pronouns at the bottom of work emails, and it’s interesting how some Lees and Sams and Camerons are against that just because they find it useful to be assumed to be a man.
A few years ago I read
The Illumination by Kevin Brockmeier, which is written in what can only be described as exquisite language and describes a few instances of soft sci-fi happenings, a bit like The Shimmer in*
Annihilation. Though I loved the novel, there were quite a few instances where I felt said language was used to obscure the events which would otherwise be straightforward. I remembered it because it’s kind of like your alien planet example: a passage describes people experiencing a slightly weird medical phenomenon, which could be, as you said, one character’s subjective experience until more and more people “get it”, leaving you to wonder if it’s sci-fi, speculative or just something like synesthesia that most people haven’t heard of. By the end of the novel it struck me that the medium’s ability to withhold information at less cost than film can be detrimental to enjoyment - it sort of gets “too clever” for no other reason than because it can.