Greek Hoplite Phalanx?

[Knight of Ne]

Could somebody help me justify the greek hoplite and heavy hoplite phalanxes. I really like the look of the units but i can never see any place for them in my armies. What do they do or have that makes them better at anything. As far as i can tell Classical hoplites are better at holding a defensive line, and spearmen seem better equipped as a fighting unit (i.e. javelins and better defense). So what exactly do they do that makes them worth the effort of using them?

Thanks,
Knight of Ne