What might be the reasons for Luffy to secretly read fanfiction?

I think it depends on how you look at it. On one hand, Luffy is always so focused on finding the One Piece and having adventures with his crew. But on the other hand, if fanfiction exists in his world, maybe he could read it for some light - hearted entertainment. However, he might get distracted from his real goals, so it's a bit iffy.

Well, perhaps in the fanfiction, they marry secretly due to some unexpected events on a strange land. For example, they might have to get married to save the local people from a certain rule. After that, they struggle to maintain their secret. Nami might be worried about how the crew will view her relationship with Luffy, especially considering Luffy's role as the captain. And Luffy, being Luffy, might not fully understand the implications of a secret marriage at first, which could lead to all sorts of misunderstandings and interesting plot developments as they journey on with the Straw Hat crew.

Maybe to protect her from his enemies. If his foes knew about her, they might target her.

To connect with other beings' creativity. Since fanfiction is created by fans, it represents a collective creativity. Narnians might read journal fanfiction to feel part of a larger community of those who are interested in their world, even if it's a fictional concept in our world. It could also be a way for them to see how the outside world perceives their home, Narnia, and its inhabitants.

One idea could be that Luffy has a secret female identity that only a few crew members suspect. For example, in some fanfictions, Luffy might use this female guise to infiltrate an all - female pirate crew or a secret society where only women are allowed. It adds an interesting twist to the character.

One interesting idea could be how Luffy's friends react when they find out. Maybe they are shocked at first but then quickly accept it and support Luffy as always.

Well, perhaps in the fanfiction, Vivi realizes her love for Luffy when she sees how he is always so determined to protect his friends and the people he cares about. Luffy, on the other hand, might fall for Vivi's kind heart and her loyalty to her kingdom. They keep their love a secret because they don't want to disrupt the harmony of the crew. And they communicate their feelings through little gestures, like Vivi making Luffy's favorite food or Luffy giving Vivi small treasures he finds during their travels.

Perhaps Nami is under a curse. The curse makes her see Luffy as a threat, even though he's not. So, she ends up hurting him because she's compelled to by the dark magic of the curse until the crew can find a way to break it.

Maybe they are just curious about how other fans interpret their own family's story. After all, in the original story, they are an important part of Harry Potter's world.

Well, he might have to learn how to act like a prince. That could include things like proper speech and manners.