Here's my way of thinking.
Can't a AV/AA MAX shoot up infantry as well?
True, it'll will probley only take out the infantry's armour before it touches their health. But those rounds are ment for taking out like 500 (or whatever level armour) a tank has. It'll rip through infantries armour in a matter of seconds.
Soldier: HA HA! Foolish MAX! You're an AV MAX, your weapons can't touch my health till you deplete my armour. By which time I will surely destroy you.
*MAX fires a 5 sec burst at the soldier. His armour is now 0*
Solider: :
O:.