what is the point of the barbarians?

[Azatoth]

In Civ II, there was this "barbarian chief" unit as well. Often well protected by the other troops (cause the barbarians had the bad habit of grouped attack - which they no longer do, makes things easier ...).
When you managed to kill all the warriors and were quick enough, you could capture him and get a ransom. Was quite useful to get a little money ...

Too bad this option disappeared

 

[Armorydave]

I find Barbarians more helpful than harmful. Not only do they provide excellent experience for my units they also disrupt competing Civ's and occasionally sack enemy cities. I always play with raging on and am considering modding them to increase not decrease their frequency.