I don't know a lot about the comic book in question, but I think it can be very appropriate at to introduce elements of pop culture into the curriculum of an English class. Education shouldn't be in the business of training children to 'appreciate the high brow.' Rather, the system should be promoting complex thought and understanding of the world around us. So, no, we shouldn't be throwing junk at these kids, but I imagine there can be a lot of important academic questions and discussions pertaining to many aspects of pop culture.
Again, I don't know the details about the comic book mentioned in the original post, but we can take something else that might seem questionable as an example. If an English teach or professor were to add Twilight to their 10th grade class curriculum, we would automatically be inclined to ask how they could possible justify this. Suppose though, that the teacher explains that the discussion points for the book will be centered around the implications of how idealized romance is in American culture, or the notion of imperfections being perfectly engineered, or even the contrast between contemporary American fiction and what are considered 'classics' (i.e. does less attention to craft hinder or liberate creativity? Can we attribute the success Stephanie Meyer's work to her laziness, the gullibility of the American general public, or a new-found sense of egalitarianism provided by mass media?), or ultimately, do mass media and marketing accurately portray reality? Do they portray an idealized reality? Do they portray sentiments of the general public via a cultural dollar vote, or the sentiments of a select view via underhanded persuasion? Also, as far as these characters; is Bella an anti-feminist archetype? Do Edward or Jacob put the same kind of pressure on men that sports illustrated girls put on women in our society? Is there really a dichotomy between Edward and Jacob, or is this struggle engineered to provide Bella with two equally appealing/unappealing versions of the same ideal?
So depending on how we are interpreting the material, there can be a lot of value in it. I think it's extremely important the kids learn to dissect even the things that seem normative and trivial so that they can better understand why they and the people around them believe what they believe. Reading Plato's Republic can only take you so far as you are willing to apply it critically to the world you live in.