The hill-fort of ancient Britain gave the chieftain military and economic advantages, as has been seen. The third advantage was social.
The physicality of the hill-fort reinforced the idea that the chieftain was in charge. Traders with questions or (more likely and importantly) village inhabitants with questions or disputes or concerns would have to trudge up to the top of the hill in order to have their concerns addressed.
Alternately, the chieftain could come down into the village; but this act still reinforced that the chieftain was coming down from on high to hear what his people had to say.
That the chieftain was up on the hill was also helpful when he wanted to keep out of disputes. The disputing parties might be reluctant to trudge all the way to the top of the hill to have their grievances aired in front of the chieftain, so they might patch up their differences without his intervention.
Lastly, the hill-fort reinforced the idea that the chieftain was important and wealthy. Who else could afford the fortifications that a hill-fort required? Who else could achieve the loyalty of the soldiers that defended him (and, by extension, the village)?
Sitting atop his hill-fort, the chieftain was master of all he surveyed: military, economic, and social.