What you are talking about is Hanno II, the leader of the "Peace" faction that opposed aggression with Rome. Hanno II, before the second Punic War, had been recognized for his conquests in Africa, and during the Mercenary Revolt was responsible for putting down mutinous Libyan tribes. Not only that, he drew most of his wealth from Libya's agriculture, which had even caught the eye of Cato the Elder (one of the reasons why he felt that Carthage must be destroyed). Libya was, like Egypt, the breadbasket of Rome and had fed the city once its population got pretty big.

It's not that the Carthaginians hadn't been expanding into Libya, however; they just did not have that much loyalty. Many Libyan tribes were subject to harsh taxation and constant levies, and were never granted full citizenship for all they have offered. This made them pretty easy to sway to another side, like what Masinissa did when he pledged allegiance to Rome, or when Utica, Carthage's longtime ally, had suddenly switched over to Rome in the third Punic War. If the Carthaginians had followed the Roman strategy (granting citizenship to conquered peoples), they would not have experienced the amount of rebellion that they had received, especially during the Mercenary Revolt.

I'd imagine what Hanno II's plan was, is to conquer many of the allied tribes of Libya, who they had to hire as mercenaries instead of formally levy. This would further enrich Carthage as they had to set up political marriages with tribal chiefs to engage in diplomacy. Would this have been a good plan instead of marching to Italy? We don't know. However, what I can say is that they should have started early with getting the Libyans on their side before the conquer overseas territories, which is what the Romans did to conquer the Latins and Italic peoples.