The poorest citizens of the Hellenic and Makedonian poleis fought as a militia roughly organized along the lines of other, more professional hoplite soldiers. They are organized in the phalanx and are quite high quality for militia, due to the dogged Hellenic spirit and fighting tradition. They can be expected to hold a line against most light and medium infantry, though they will be devastated by missile troops, as they have virtually no protection from missiles aside from their shields and the bodies of their compatriots. They are still useful against cavalry as no horse will willingly charge a bristling wall of spear points. Hoplitai Haploi, if used properly, can be an inexpensive and very valuable unit. And though they will be outclassed against heavier and more professional troops, they can, if well supported, hold the line far better than one would expect of a militia.
Historically, the poorest citizens of any polis and the peasants on the estates of Makedonia were called up in defense of their homeland to fight as militia. They had been used to devastating effect in many ancient battles while forming the second line of battle. They were good and courageous soldiers that fought with a degree of discipline and courage that would not be thought possible of an unprofessional milita. They were not cowards and did not break quickly, but were often annihilated if facing good missile troops or heavier, more professional infantry. Peltastai and other units armed with javelins were particularly devastating to the militia hoplites, due to their lack of protection on the battlefield.
The Hoplitai Haploi are one of the best units to have in your army at the start of your campaign. They are relatively cheap and their morale and shield bonus makes them excellent flank guards. They can be used in liaison with lighter infantry or skirmishers like the Peltastai and Thureophoroi to provide cover, or they can be used to protect the flanks of your main phalanx line against infantry or cavalry assaults. Their light armour also provides mobility, meaning they could just as easily be used as flankers, or to chase away enemy skirmishers.
Hoplitai Haploi are best used in Guard Mode. This gives them a coherent formation, and prevents them from tiring too quickly. In Guard Mode they can hold out much longer against enemy infantry, giving you the time to either outflank the enemy or utilize traditional Hammer & Anvil tactics. Due to their lack of armour, Hoplitai Haploi should not be used as main line infantry, especially not against heavy or shock infantry. Players should also try to keep them away from concentrated missile fire, as the AI is most likely to aim for the least protected units. Akontistai and Peltastai should be carefully avoided, as their hit and run tactics can deliver a serious blow to the careless player.
In conclusion, Hoplitai Haploi are excellent starting light infantry, that can be used for a variety of roles on the battlefield. Later in the game when the player has more money, the Haploi should be replaced by the less mobile but much more trustworthy Hoplitai.
Below is a picture that shows the AoR (Area of Recruitment) of the Hoplitai Haploi: