The combat roles for each is different . Battle Armor and Infantry have the same position offensively and defensively . That means they are part of an offense to secure the battlefield for immediate Salvage . As a defensive unit they are area denial tools but have to get to the area to deny the enemy before the enemy does. Protomechs job is to use their speed to go in advance of mechs and elemental to prevent infantry and battle armor from getting to and hunkering down before the mechs and elementals get there. In an Invasion they quickly seize civilian infrastructure so they can cut off power and water to the parts of that is being contested over. The only role they truly share is policing rear areas and city streets vs mob units as described in the Unification hWars book . The best way to disperse mobs is tear gas in conjunction with snipers with rubber bullets . There are a host of unit types that can deploy the class 1 chemical weapon that is tear gas proto mechs with grenade or missile launchers included. Proto Mechs only strength is speed that is important to minimize the damage mobs can do and gives the civilians a strong sense of who is or is not in control. Battle Armor speed weakness can be offset by fast APCs , mass transit or support vehicles such as from the " Has anyone tried " post in the fan design board. The earlier proto mech designs performed so badly I stopped considering them as a good combat unit. Check out what air burst rounds with a mech mortar eight does . Kill half a platoon of conventional infantry , damages a squad of med battle armor or better but kills none with one shot and guts most proto mech formations. Bottom line proto mechs engaging battle armor by beating them to the area the defenders wish to deny the advancing enemy mechs and preventing or just engaging the before they can hunker down at a pre prepared hardend position even if the proto mechs lose should weaken the position so it does not cost too much to go through it with Clan unit that matter and is valuable . A proto mechs job is be disposable cannon fodder and are considered successful if they take down or tie any enemy assets .