For the author it matters. To which degree do they want to be associated with the resulting text.
And I differentiate between "Matt Godbolt" who is an expert in some areas and in my experience careful about avoiding wrong information and an LLM which may produce additional depth, but may also make up things.
And well, "discern the quality of the contents" - I often read texts to learn new things. On new things I don't have enough knowledge to qualify the statements, but I may have experience with regards to the author or publisher.
and what do you do to make this differentiation if what you're reading is a scientific paper?
Same?
(Some researcher's names I know, some institutions published good reports in the past and that I take into consideration on how much I trust it ... and since I'm human I trust it more if it confirms my view and less if it challenges it or put in different words: there are many factors going into subjective trust)