One possible reason could be for disguise. Maybe he is on a secret mission and doesn't want to be recognized easily. In the Naruto world, there are many dangerous foes, and wearing a face mask can help him blend in or hide his identity from those who might be targeting him.
Another possibility is that Naruto wears the mask as a tribute to Kakashi after a significant event. It could be that Kakashi sacrifices himself to save Naruto and the village. So, Naruto dons the mask to carry on Kakashi's legacy and to always remember the lessons he learned from him.
Animal prints such as leopard or zebra are also trendy. They add a bit of wildness and fun to the mask. Abstract geometric designs are another option, which can be very modern and eye - catching.
A possible plotline could be that a new enemy targets Kakashi because of his distinct face features, believing there is some hidden power in his appearance. Naruto then has to protect Kakashi. Another plotline could be a magical spell that gets cast on Kakashi's face, changing his expressions uncontrollably, and Naruto tries to find a way to break the spell.
If it's a more spiritual fanfiction, the mask could have a connection to the spirit world. Naruto wearing the mask could open a portal to that world or allow him to communicate with the spirits of past ninjas. He could then seek advice from the great ninjas of the past through the power of the mask.
One creative way to use a Naruto face mask in fanfiction is as a conduit for chakra transfer. Suppose a character is injured and another character uses the mask as a medium to transfer their chakra, kind of like how Naruto sometimes shares his chakra with his friends. The mask could have been specially designed for this purpose by a master ninja. Also, the mask could be a communication device. It has some sort of jutsu - powered technology that allows the wearer to communicate with other characters over long distances, just like how Naruto communicates with his allies during battles.
Well, for starters, Kakashi has to deal with Naruto's hyperactive and sometimes reckless behavior. Naruto often acts without thinking, which could put him in danger. Sasuke, with his complex emotions and the burden of his clan's massacre, is also a handful. Kakashi needs to make Sasuke understand that revenge is not the only way forward. Additionally, Kakashi has to ensure that both Naruto and Sasuke get along well with each other. There could be rivalry between them, and Kakashi has to manage that in a way that doesn't harm their relationship or their growth as ninjas.
One possible plot could be that Naruto discovers a special face mask with hidden powers. For example, it might enhance his senses when he wears it, allowing him to detect enemies from a greater distance. This could lead to new adventures as he has to figure out how to control and use these new powers while still being himself.
I'm not sure specifically as I haven't directly read this story. But generally, it could be about the over - reaction or excessive concern regarding face masks that was presented on Good Morning America. Maybe it was about people's extreme reactions to mask mandates, shortages, or misinformation related to face masks.