The author is trying to distinguish between "wallflower" the "socially awkward person" and "wallflower" the "person who stands near a wall". They are using a slightly more literal definition, but not the most literal (i.e. the plant).
The justification is that "being near the wall" =/= "being in a high-traffic area".
Re-read the quote I have in my comment and remove the word 'literal'. Does that sentence have more, less, or the same meaning / power to you?
With 'literal': don't stand by the wall
> There’s a moment in your book that I love, when you give advice to awkward people looking for social shortcuts, and you tell them not to be literal wallflowers.
and
> There’s a moment in your book that I love, when you give advice to awkward people looking for social shortcuts, and you tell them not to be wallflowers.
There is a non-trivial difference in connotation between the two sentences.
In vernacular conversation "wallflower" can be used as a term to connote (strong) shyness or to indicate generalized presence on the periphery of an event. In the sentence from the article, "literal" helps to shift emphasis away from the "shy" connotation. Without it, or some other way to emphasize connotation, the sentence is easier to misinterpret as follows:
"..., and you tell them not to be too shy."
alternative
"4. in effect; in substance; very nearly; virtually: I literally died when she walked out on stage in that costume."
I'm a long-term fan of the Sapir-Whorf hypothesis (and accept that it's not without dispute).
"I literally died laughing" doesn't mean the same thing as "I died laughing", either. "Literally" functions as an intensifier here, and therefore the former sentence is stronger.
Would you be happy with 'I died laughing ...' when people describe something especially funny? (I would, for the record.)
And/or do you think 'I literally died laughing ...' (when people didn't actually die from laughing) to be more emphatic / compelling a commendation?
If someone said 'I literally died twice from laughter ...' would that be doublepluscompelling?
Then you would already be OK with something analogous to using "literally" as an intensifier.
Since, of course, "died" also means something specific that's unrelated to laughing, and the person uttering the phrase doesn't imply that they actually died.
>If someone said 'I literally died twice from laughter ...' would that be doublepluscompelling?
No, that's why people don't say it. It's the historical evolution of language that dictates what's "doublepluscompelling" or not, not some a priori rules.
like
In Vulcan it's usually frowned upon, but human languages often use nuance, play, context, and (gasp) more than one word for the same notion.
Moreover, the value of a word is not in its definition, but in its use. Even if "literally" (in this usage scenario) means the same as "figuratively" they both have very different connotations and impact on the listener.
> There’s a moment in your book that I love, when you give advice to awkward people looking for social shortcuts, and you tell them not to be literal wallflowers.
The anecdotal clarification there is that people in dormitories should ensure they are near the entrance -- precise details not provided.