Okay so one of my favorite things about Kingdom Hearts is how they make the dissonant IPs of Disney and Final Fantasy mesh together. It obviously clashes visually, though Nomura does a really good job tying the two together through Donald and Goofy's outfits and Sora's overall design. However, in spite of the visuals and the general opinion that the story is overly convoluted, Kingdom Hearts actually uses it's narrative and themes to make a story that has a meaningful narrative cohesion.
Many stories from Japan share themes of friendship and perseverance, Kingdom Hearts is no exception. However, rather than simply keeping those themes as abstract concepts, Kingdom Hearts  makes them into tangible forces in its world. It is treated as another in universe system of magic Disney creates like "True Loves Kiss".