Phalangitai Deuteroi can be used as decent defensive infantry, well able to hold their own against most enemies provided that the enemy is attacking from the front.
Can Form Phalanx
The Phalangitai Deuteroi are wealthier members of Makedonian or Epeirote society than the majority of peasants, but are still not in the class required to be considered Pezhetairoi (voting property owners), yet they can afford better equipment than their poorer taxeis Hoplitai brethren. They are armored in good Phrygian helmets, quilted cloth armor that can dampen the effects of missiles, and are armed with the dreaded sarissa, a six meter long pike. They are disciplined enough to hold a line well, and as property owners, have a lot to lose if a battle does not go their way. They can be used as decent defensive infantry, well able to hold their own against most enemies, so long as that enemy is attacking from the front. They are still vulnerable to missiles and flanking attacks, though not as vulnerable as their less wealthy compatriots. They are more disciplined and better motivated than their Asian or Aigyptian counterparts in the armies of the Seleukeis or Ptolemaioi.
Historically, the Phalangitai Deuteroi were only used during periods of extreme need or times when Makedonia was invaded. They represent the lower end of the smallholder class, and as such, are the primary food providers of the social order. They were used only rarely, usually during invasions. They did give a good account of themselves against the Galatai and Thraikes invaders, but were found wanting as the armies of Philippos V and his son were cut down by Romaioi soldiers.