One Piece

[neflight86]

...then what's the point of Yamato telling us about it (or it even still existing) unless there were a few important details saved for revelations later? Does Luffy need to know about Odin's diary to want to beat Kaido? Yamato was convinced by the boiling oil stunt to want to be Odin, so it wasn't an inspiration, leaving me to assume it still has more information glossed over or omitted from the flashback.

[DarthEnderX]

...then what's the point of Yamato telling us about it (or it even still existing) unless there were a few important details saved for revelations later?

Well, for one thing, WE know about Oden's journey, but the Strawhat's don't. The journal gives the Strawhats a way to learn what the audience knows.

Also...it probably tells where the last Red Ponyglyph is.