I think the attraction to Westerners is that it's entirely different than what you're exposed to. In Japan, anime and manga is considered an art of storytelling. Storytelling takes time, time to develop the plot in several hours than we do in our usual 2 hour movies. In western culture, the focus in entertainment is reaching the goal of the protagonist quickly, while still having your attention and cognitive connection, while over yonder it's about the journey, not the destination.
I can see why that can appeal to many, especially if they want a deeper connection to their own entertainment. I'm pretty fond of it. Extremely picky, but fond. I can't deny it, but most animes are pretty much crap