I mean...if I am looking at two comics that are the same grade, let's say 4.5 for each. Personally, I want the 4.5 that is all attached and does not contain certain defects like stains. So maybe one 4.5 has more cover wear and the other is sharper but has some light staining. I will put my money towards the 4.5 with a bit more wear and would pay slightly more for the copy I prefer.
So I guess in a roundabout way, yes, grader's notes could affect the grade if you have a collector like myself who tries to avoid certain flaws. Otherwise, it comes down to appearance. The 4.5 that looks better should sell for more...and that can be determined by simply seeing the book and page quality, the grader's notes likely factor in little here.
There is also the potential for grader's notes to help increase the value, especially if the flaws noted are all "bends and indentations". Someone might see that and get aspirations of pressing a 4.5 book into the 5.5-6.0 range, so they might spend a little more if they know the flaws from the grader's notes and feel that they can obtain a grade bump after pressing and cleaning that book.