Here's what matters: a 3D vector is one object with three properties. Instead of tracking three separate arrays for , , and coordinates, you create a class that groups them together.
I'll show you why this helps. With a Vector3D class, you can write methods like add() or isZero() that work on the entire vector at once. Your code becomes cleaner because related data and operations live in one place.
This pattern appears whenever you have multiple values that belong together. Position coordinates, RGB colors, student records - any group of related data benefits from class encapsulation.