What is the most demeaning thing said about you as a writer?
"Let me know when you stop writing comic books and start writing real books, and I'll check out your stuff."
Second, try writing comics. I dare you. It's not easy. I daresay it's harder than writing so-called "real" books because a writer has to think not just in words, but in pictures and then describe those pictures in straightforward language without the benefit of 60 pages of describing the Tolkienesque mountains along the journey.
Third, comics are real books. Nowadays more than ever. They have the same fancy hardcover bindings and long page counts. And in many cases, as much dialog and internal monologue as a novel (they just do the narrative descriptions with pretty pictures and not words).
Fourth, I have written "real" books now too (to use this person's definition). Have you bought one yet?