How would that even make sense in a 3D context? If you need the particles to span vertically (why?) then you will need to create new particles for every y-value.
Hmm? Does that mean I can now latitude and longitude alone to figure out where you live? Makes a lot of sense, who needed altitude anyways!
Fact: Vector3 contains everything in Vector2 and completely works as if it extends Vector2, but it does not have any inheritance relationship with Vector2 at all.