How are they relevant in the modern day society?

In those days, it used to be their decision on what to do and what not to, on who should be rewarded and who should be penalised, they would call the shots on steps pertaining the economy of their domains.

Today we have a parliamentary system of government that operates on democratic rules, justice is now served in the court of law, no king can put someone in the dungeons as before because there is prison, the kings don't have power over the economy again, in fact they get paid, I just can't quite figure, do they still have significant importance again in a country like Nigeria?