What explains the stability of Cation, which came to the destruction of Carthage?

Because he believed that Carthage posed a great threat to the existence of Rome. So in 149 BC the second Punic War was unleashed. Here Carthage was only on the defensive. The fighting lasted three years. In the final phase of the war, the Romans besieged Carthage and stormed it until the defense was broken. After that, the Romans burned and destroyed the city. We can say that Carthage was wiped off the face of the earth.