And perhaps more to the point, in Africa you will be fighting lots of skirmishers with no armour. Easily recruitable competent archers are a real godsend for dealing with all these. Especially the numidian skirmisher cavalry that are too damn fast for anything else to kill off. Of course the carthies bring plenty of heavy stuff at first that archers wont be much use against, but they always have enough light support that you will have more than enough enemies to shoot at.