Perhaps as a sign of rebellion. If Naruto has some issues with the established norms in his village or with the ninja system in general in the fanfiction, getting piercings could be his way of defying authority and showing that he won't be restricted by the traditional ways.
A wife may also get a piercing as a form of celebration or milestone. Let's say she just achieved a big career goal or completed a difficult fitness journey. She might decide to mark that moment by getting a piercing. It could be a way to feel a sense of accomplishment and give herself a new look. And sometimes, it can be just for the fun of it. To try something new and exciting in her life and see how it makes her feel.
One reason could be a change in self - identity. Maybe she wants to break away from the traditional image society has of a 'wife' and express her individuality more freely.
One reason could be a change in personal style. As people grow and evolve, their fashion sense changes too. So, she might want to update her look with new piercings. Another reason is for a special occasion. For example, if she's going to a formal event, she may choose more elegant piercings.
She might want a new look. Maybe she was bored with her old appearance.
One reason could be his status as a jinchuriki. People might be afraid of him because of the Nine - Tails inside him, so he feels unloved. Another reason is that he was an orphan, and without his parents around, he may have felt like he didn't have that family love that others had.
One reason could be that some fans are very purist about the original Naruto story. They might feel that fanfiction often distorts the characters or the plot in ways that go against the essence of what Naruto is all about. For example, changing a character's personality completely to fit a romantic or dark and edgy narrative that doesn't align with the source material.
There are several possible reasons. For one, it could be a way to subvert the expectations of the Naruto character. In the original series, he's so pure and full of life. By having him smoke in fanfiction, writers can create a contrast. It might also be used to set a certain mood, like a gritty or more adult - oriented atmosphere. Additionally, it could be a symbol of his rebellion or a sign of him breaking away from the norms of his ninja village. Writers might use it to explore a different side of Naruto that wasn't shown in the original story.
One reason could be the waning popularity of the Naruto franchise over time. As new shows and series emerge, some fans shift their attention away. Another factor might be that the quality of fanfiction has declined. With so many people writing, there's a lot of poorly written stuff that turns readers off.
One reason could be to explore a different character arc. Writers might want to see how Naruto would develop if he had a more violent nature from the start. Another reason is to add drama. A bloodthirsty Naruto would create more conflict within the story, especially with his friends and the village. Also, it could be a way to show a more 'realistic' or gritty version of the Naruto world, where characters are not always so morally upright.
One reason is that some fanfiction authors may lack a deep understanding of Naruto's character. They might write things that are completely contrary to his values and personality just for the sake of creating a 'unique' story. For example, Naruto is known for his positive attitude and strong will, but in some fanfictions, he could be depicted as a negative or spineless character.