It could be the key to solving a major mystery in the story.
The jewel might make Sakura a target, which would create a lot of action and drama. Enemies could be after it, forcing her to defend herself and the jewel. This would lead to battles and tense situations. Also, it could be that her friends are initially suspicious of the jewel, which would cause some internal conflict within the group until they understand its true nature.
In many fanfics, such a jewel could be a magical or mystical element. It could be a source of her strength, like giving her the ability to perform special jutsu or have enhanced senses. It might also have a connection to her relationship with Sasuke. For example, it could be a gift from him in the past or something that binds them together in a special way.
Sakura's injury can strengthen the SasuSaku relationship. It can make Sasuke realize how much he values her, and he may start to show more affection. For instance, he might give her a gentle touch or a worried look, which is different from his usual cold demeanor.
If Sakura dies in a fanfic, it could have a huge impact on the whole Naruto -verse within that story. Her friends like Naruto would be deeply affected. Naruto might feel like he failed to protect her, just as he felt about other losses in his life. And for the medical ninja community in the fanfic, her death could be a big blow as she was a talented medic.
In these fanfictions, Sakura often develops more resilience. Being in the hospital, she has to face her own physical limitations, which makes her stronger mentally. For example, if she's injured and can't use her combat skills temporarily, she might focus on her medical ninjutsu skills more. This also deepens her understanding of her role as a healer in addition to a fighter. She may also become more open about her feelings for Sasuke, especially if she thinks she might not have another chance to express them.
It can lead to a shift in Naruto's character development. Instead of having a romantic arc centered around Sakura, he may focus more on his ninja duties or form different friendships. This could make him more independent and less influenced by the idea of winning Sakura's heart.
It might explore different aspects of Sasuke and Sakura's characters within the context of a fanfic. For example, it could show Sakura with different abilities or Sasuke having a different attitude towards her. Since it's a fanfic, the author has the freedom to deviate from the original storyline and create something new. It could also be about their relationship in a different time period or setting, like in a modern - day AU (alternate universe) or in a completely fictional world.
A fanfic could show Sakura sacrificing herself to save Sasuke. This would be a very emotional and heroic end for her. Sasuke would then have to live with the guilt and the memory of her selfless act.
She might be initially shocked. Sakura has always seen Naruto as a friend, so learning of his romantic feelings could completely change her perspective of him. It could make her re - evaluate all their past interactions.
Her friends would be extremely worried and would do everything they can to support her. They might feel guilty if they think they could have prevented her memory loss. Her family, if there are any in the story, would be heartbroken and try to take care of her like she was a child again.
It could strengthen some relationships. For instance, if there's a character who really understands her decision to cut her hair, it might bring them closer. They could share a deeper bond over her new look and what it represents for her.