Armed with javelins for harassing enemy formations they can cause a surprising number of casualties. They do poorly at melee and are best used only as skirmishers.
Armed with nothing but a small shield and a handful of javelins these men risk their lives in closing with the enemy with only the lightest of equipment. These men deploy in a cloud before the heavy infantry dashing back and forth to release their deadly missiles. These infantry skirmishers fought in open formations so as to maximize the number of men able to get a throw and minimize the effect of enemy missiles. Lacking armour, training and heavy weapons these light infantry stand no chance if committed to melee.
Historically, most armies of the classical period found use for poorly equipped levies as skirmishers, very often as javelinmen, as these troops required relatively little training and financial investment, relying mostly on widespread natural skills and scant gear, while still providing some useful service.
The Gun-i Palta, when used correctly, can be dangerous assets to any army. Being cheap and having a wide AoR (Area of Recruitment) means they can be spammed and used as "suicide units". Suicide units are units that a player uses for the sole purpose of either luring the enemy into a trap, diverging the attention of the enemy away from the main battle line and providing the rest of your units with cover against missile fire. All of these usually result in the "suicide unit" sustaining severe casualties or even routing in the process.
Apart from suicide missions, Gund-i Palta can also be used as traditional skirmishers. This means peppering the enemy with javelins before the main engagement in order to thin out the enemy lines, followed by a quick retreat to safety. In that sense, it is wise to keep Gund-i Palta in Guard and Skirmish Mode, the former to ensure they will not be forced into combat with an engaging enemy unit and the latter to have them automatically run away from approaching enemies. Their great numbers means many javelins, and so even after initial skirmishes there are usually some volleys left that can be used in the course of the battle for many purposes. Furthermore, they can also be used to eliminate strong enemy missile units. Missile units like the Toxotai Kretikoi and Sphendonetai Rhodioi can be a serious threat when used properly (usually the case, even with AI control), mainly because they have very long range and can eliminate entire cavalry or light infantry/missile units if left unchecked. In case of an encounter with such units, the utilization of a few Gund-i Palta units is ideal as they a) attract enemy missile fire when placed in front of the army, and b) are very effective against lightly-armoured units thanks to their javelins.
Javelins are especially deadly when fired from elevated terrain towards an approaching enemy, so placing the Gund-i Palta on high ground or on top of city walls will deliver extra damage to the enemy. Also, firing a couple of javelin volleys at the exposed backs of enemy units that are engaged in combat is usually sufficient to cause a rout. That, coupled with their intrinsic mobility, makes them suitable for flanking maneuvers as well, provided there is no cavalry or infantry to do the job instead.
Even so, Gund-i Palta remain ill-armoured and undisciplined, and as such should avoid direct combat with even the lightest of infantry units. Cavalry should also be watched out for, and so in order to provide the Gund-i Palta with protection it is a wise idea to keep mobile light or medium infantry like the Pantodapoi (Hellenic Native Spearmen) and Thureophoroi closeby. Cavalry like Hippeis and Prodromoi can also accompany Gund-i Palta in order to make sure enemy cavalry do not attempt to engage them.