All they do is complicate things. In today's society where communication is easier across long distances, we should have a set Earth time. In each respective area, people will learn what time the sun rises and what time it sets. Communication and correlation over long distances would be simpler, and keeping track of world events would also be easier. Agree or no?
Edited: 4/12/2014 3:11:11 AM PermalinkErm no. A system where we have a set Earth time would not work out well. Rather than having to learn an offset (which allows you to do simple math), you'd need to memorize what hour morning / night is for that particular timezone and juggle all of that in your head. "Oh, I want to call my friend in Sweden, goodness, it's 7PM Earth Time, but I don't know what time of day it is over there! Is she sleeping? Guess I'm going to have to go look it up!" It really wouldn't simplify communication or correlation as a result.