Reading Palahniuk doesn't make you feel good about yourself. You don't become a better person having read his works. Your life becomes no more significant than it was before, necessarily.
It's like looking at Picasso's works. You don't admire them for their beauty. They don't show that you have a true appreciation of art. Or abstract even.
These men, their works, inspire. And not in the, "I'm going somewhere," "I can achieve greatness," "the world is my canvas," sort of way. But in a way more subtle. They challenge you to think. To look back at all that is crooked and easily undefined or more commonly over-defined.
Palahniuk, like Picasso, is giving you another approach to observing, to viewing. To thinking. To appreciating. To approaching life. He takes your world and, with words, tears it apart from the seams. He realizes all vantage points and selectively adheres new perspective to parts/people/places you already know.
And he is not doing it for you. He just does it because he can. If he knew that not a single person would read it, he would probably still write it anyway. Because he is a writer. Because that is what he does. Because he thought it. Or knew it. Or figured it out. And even if he weren't guaranteed readers, in written form, it would at least have the potential to be read. Even if just by himself again, years down the road.
How selfish would we be to keep our thoughts to ourselves? To keep our epiphanies, our revelations, our discoveries limited to those who epiphanized, revolutionized, discovered.
Still- How selfish would we be to expect that someone actually cared about every thought that we've had? Or any? Any epiphanies, any revelations, any discoveries. They may have seemed significant to us but why do we care if or hope that someones else learns of/from them?
Even the diary of Anne Frank, presumably written for her own eyes, is shared and studied and applied to modern day morals, philosophies, history lessons, etc.