I dont get it?

I suppose it's popular because it's a facade of reality; Everything's quite pleasant or magical.. Same reason as to why people like Sci-Fi or Fantasy movies and such; It provides a better picture of reality and is a major source of entertainment. Anime always has and probably always will be.. "controversial", some will despise it and others will love it. I enjoy it myself, however, I've met plenty of souls who've hated it.