Talking of picture books, while it is not necessarily easier to read, it is harder to lose track than text-only.
I wonder a little if anyone is interested in non-fiction? For example, this one - 講談社 学習まんが 日本の歴史（全２０巻） 無料試し読み版 - 文芸・小説 講談社（講談社 学習まんが）：電子書籍試し読み無料 - BOOK☆WALKER -
