What are the advantages of iron tools and weapons over stone and copper?

What are the advantages of iron tools and weapons over stone and copper? What military innovations did the Assyrians use?

Stone and copper tools are fragile enough. One awkward movement – and the tool bends, splits, which forces you to repair it or create a new one. Iron, on the other hand, is much stronger, although corrosive, but still a more practical material.
As for the Assyrians, it was their army that was the first to be equipped with iron weapons and armor. They also began to use cavalry, reconnaissance, created a regular army, uniform and divided into types of troops.