Except, however, he had to fight pitched battles in order to earn allies in Italy and that course was set even at beginning, since he knew conducting a long siege in hostile land was impossible. Unless, of course, he naively believed burning a few country sides would spark a mass Latin revolt against Rome, probably based on this idea from extreme poor intelligence collection and personal bias (and poor intelligence work is one indication of poor generalship).
Except Hannibal would not know what Scipio's goal was. In fact, there was a high possibility that Roman would split their force and pushed into defendless Iberia while checked his expedition force in Gaul/Italy. Hannibal's die-hard Italy march left no solution in that possibility, and in fact doomed himself in long term since Roman did establish a bridgehead on Iberia and prevented any communication between him and Iberia.
Entered and fought in Italy, then what? The fact was that he still needed to fight Roman in pitched battles in order to convince Latins to desert Rome, especially since siege was out of options. Again, like I already point out, unless he naively believed that burning a few country sides would turn Latins against Rome, his plan was largely based on false assumption and personal bias, without even some basic intelligence collection of Latin cities states before even rushed the expedition.
Hannibal's only hope was to fight pitched battles against Romans in order to convince Latins desert Rome, and if pitched battle was ultimately inavoidable (and probably his goal), then why not fight in at a best place where the terrain was familiar and supplyline was short? Why chose a place when he was in complete disadvantages (lost 1/3 of veterans, unfamiliar regions and supplyline completely cut-off with no hope of reinforcement) and offered a battle that was his goal/only choice at first?
And of course, lets not even discuss his poor intelligence work.
And? That does not answer why he could not destroy Roman near his Iberia base where the supplyline was short, and then move opposely to Cisalpine Gaul without crossing Alp.
And yet, that was Hannibal assumed that Rome would put all force to pin him down; he completely ignored the high possibility that Roman would only send some force to check his expedition force while other forces would push into defendless Iberia without difficulty - means the doom of his supply base obviously.