On the positive side, he can use it to protect Hogwarts. He could be like a living, breathing firewall against any fire - related attacks on the school. For instance, if the Dark Lord tries to set the castle ablaze, Harry can use his fire - controlling ability to counteract the flames and keep the students safe.
His relationships with his friends might change. Some friends could be in awe of his new power, while others might be a bit afraid. Also, it might change his role within the school. Instead of just being the Boy Who Lived, he now has this additional identity as the Fire - Controller, which could bring new responsibilities and expectations.
He might also face moral dilemmas. For instance, using this power to heal someone might seem noble, but if he uses it to harm or manipulate others, it would be a different story. He has to constantly struggle with the right way to use this power.
One consequence could be that the wizarding world starts to view him with even more suspicion and fear. People are already afraid of dementors, and if Harry can control them, they might think he's becoming too powerful or even turning to the dark side.
Not being able to create control groups in the Starcraft 2 story can make the gameplay feel more restrictive. You might find it harder to adapt to different in - game situations. For instance, when facing a sudden rush of enemy units, in a normal game with control groups, you could quickly gather your defense units. But in the story, you have to do it in a more cumbersome way, which can be frustrating at times. It also changes the overall pacing of the game as you spend more time on unit selection rather than on actual strategic decision - making.
One implication could be a change in his combat abilities. He could use metal objects as weapons or shields more effectively. For instance, he could make a sword fly towards his enemies or create a metal barrier to protect himself.
One consequence could be that he becomes more curious and starts to explore places he shouldn't. Since he can be invisible, he might sneak into the restricted section of the library or into the teachers' lounge to uncover secrets. This could lead to him getting into trouble or finding out important information that changes the course of the story.
One implication is the moral dilemma. Percy would have to decide when and how to use such a powerful and invasive ability.
One advantage is better defense. He can quickly grow thick bushes or tall trees to shield himself or his allies from attacks. For example, in a battle against powerful ninjas, he can create a forest around them for protection.
The fact that Naruto can't read or write fanfiction doesn't have any practical consequences in his own universe. His story is about his journey as a ninja, his growth in power, his friendships, and his fight against evil. Fanfiction is an outside concept that doesn't play a role in his story. He doesn't need this ability to succeed in his own world of ninja battles, village politics, and personal development.
Another consequence is that it would change his relationships within Hogwarts. His friends might be a bit scared or in awe of him having such a unique ability. Some students might be jealous. Teachers would also have to figure out how to deal with this. For instance, Professor McGonagall might be worried about how this new ability would affect Harry's studies and his place in the school. And Harry himself would have to learn to control this ability and not let it go to his head, as it could easily make him become overconfident or reckless.
One possible consequence is that it could change the dynamics of his battles. He could easily surprise his enemies and gain an upper hand in combat. For example, he could sneak up on opponents and land a powerful attack without them even realizing he was there.