Tanks also give little organization, so you will have to combine them with infantry, preferably motorized so they can keep their speed up instead of crawling around at infantry speed.
Armour is lacking in softness, so if the enemy has a lot of soft attack(infantry with artillery) you can counter them with tanks, who will take greatly reduced damage. Infantry is soft though, and soft attacks work well against them. They lack organization, but your infantry will provide that, and they pack a lot more punch than the infantry and will allow your infantry to inflict greater losses against the enemy. The easiest way to give your infantry armies extra firepower, would be to create some artillery brigades in the last slots of your infantry.
They are cheap to produce also as they only require small arms and support equipment. All infantry armies generally lack firepower, but they have decent staying power because of their organization.
