Wow, a Louis Arnot callback was definitely not on my Elbaph Bingo Card.
But, interesting, that the book he was mentioned in "Brag Men" was worthy enough to be saved by the Oharans back then from the Buster Call. It was also mentioned in the Ace Novels, and ultimately the reason that Ace didn't starve to death.
A book with many different tales and stories about adventurers on the Grand Line so unbelievable, that most people would think they are lies, there is definitely a connection to Usopp here. Lokis Hammer on his back in the last chapter was already a great reveal, but this is also intriguing.
And the Mystery Person at the End, of course. Now that I look at it again, Crocus looks like he was proudly talking about his adventures on Roger's Ship to that Person in the Cover Story.
Usopps lies that become true at the End will go around the World in a book like this, inspiring many people in different Life Situations. I see where Oda is going with this. This is awesome. I never even thought about an option like that.
Just like Kaya was saved from her depression and Ace was saved by Masked Deuce from dying after the book inspired him in the Novel. It will help so many people.