I think a lot of people found it helpful because it really puts a label on your story that might be unnecessary. It's telling people (much like it was telling us mods) that it's an intensely graphic, violent or pornographic fic and that seemed to be way too high a rating for a lot of the fics that were calling themselves NC-17.
I agree. I tend to be very deatailed in my writing, and so, where the love/sex scenes where concerned, I felt that rating was the one to go with. However, now I see that's not the case, although it comes up now and then. My writing has a theme, plot, and a definite purpose with and overall meaning. It's not just about the love story... haha, these charcters are going places.
So thanks Julily, for clearing the waters!