It's worthwhile. Even if you're writing fan fiction, and never hope to profit from it, it's something you put time and effort into. It's a piece of your soul, and having it stolen is a violation. We get that, and we are willing to work hard to keep our site free of plagiarists.
Readers know that if they email us with a report, it will be investigated thoroughly, and it will be dealt with quickly if it is a valid report. It doesn't take thirty people reporting daily for two months to get our attention.