[davidgtl]

everything is discrete if you look fine enough. locally (household-fine) what you say would be nice, however the moment you start travelling informational nightmares would ensue due to human nature, nobody (in the grand scheme) would use the UTC time since local is more useful/frequent so all travellers need translators which can seamlessly translate local time to be as useful as current narional timezones are. such a translator would either be manually preprogrammed(cumbersome) or GPS, computer-powered which brings its own troubles. I think countrywide(as in european country or american state) is a pretty good scale tradedoff between ease of use and accuracy which is here to stay until GPS and computation are ubiquitous(as in every grandma has access to a smart device with GPS she can leave on all day and can be read as easily as a wall clock while having dough all over her hands) sorriez for wall of text :)