In the context of film and TV criticism, saying something is "good paper" often means the or screenplay was exceptionally well-written.
If you are looking for why the episode itself is considered "good paper" (high-quality writing): The Last of Us 1x6
If you are referring to physical media or collectables for Episode 6: In the context of film and TV criticism,
: Episode 6 is one of the most highly-rated episodes of the series, praised for its emotional dialogue between Joel and Tommy and the pivotal confrontation between Joel and Ellie. The Last of Us 1x6
While the specific phrase "good paper" does not appear as a widely recognized technical term for ("Kin"), it may refer to discussions regarding the episode's script quality or physical merchandise associated with the show. Script & Writing ("Good on Paper")