[astura]

It sounds like a decent idea on the surface but then times would be meaningless. Right now a time "means" the same thing everywhere. When we ask "what time is it in Japan?" we understand the answer. We understand when its "noon" in Japan, we know whereabouts in the day it is and what we can expect people to normally be doing, ex, eating lunch. If it's 3am in Japan we know its not a great time to call beyond emergencies.

If you're in the East Coast US and its 5am and at the same time its also 5am in Japan, but they mean different things, you no longer "understand" what time it is in Japan. You don't really have much of a way of answering "is it a good time to call someone in Japan?" - You have to figure out a way to "translate" from your time to theirs. It would be very, very confusing. So in the end you'd end up re-inventing time zones.

It only works if nobody knows anything about other parts of the world.