Concept: “It's not only a box.” 
Content: It’s a sturdy box, with 6.25" x 9.25" x 2" of room. When you drop a d6 in it, terror happens.
Writing: Entire encounters, condensed on a lid. Full of flavor, and terror.
Art/design: Sharp illustrations, clean text, elegant drop table design.
Usability: Can hold things, so you can roll things.