Why did the troops of Carthage conquer a significant part of the Iberian Peninsula to fight Rome?

In order to have a permanent foothold from which to carry out attacks on Rome and its armies. In addition, the occupied territories supplied Carthage with human resources and food, the delivery of which at that time was very problematic. Let us not forget that many tribes in the occupied lands voluntarily went over to the side of Carthage, considering the Romans as their enemies. After the fall of Carthage, Rome, conquering, made the Iberian Peninsula its province. And now the state of Spain is located there.