They are presented attractively for the same reason that kittens are cute - so that they can draw you in, then pounce on you for the kill. Seriously. Stay away from kittens.
Brandon SandersonAuthors also create lovable, friendly characters, then proceed to do terrible things to them, like throw them in unsightly librarian-controlled dungeons. This makes readers feel hurt and worried for the characters. The simple truth is that authors like making people squirm. If this weren't the case, all novels would be filled completely with cute bunnies having birthday parties.
Brandon SandersonWhen I write my books, actually I'm known for very logical rule-based magic systems. I write with one foot in fantasy and one foot in science fiction.
Brandon Sanderson