I agree it's not perfect but: 1. For cases where seconds matter in human interaction there are well know and efficient protocols to sync 2. Often 2-3 seconds

I agree it's not perfect but: 1. For cases where seconds matter in human interaction there are well know and efficient protocols to sync 2. Often 2-3 seconds turn out to not matter but being on the right time zone does. It is an evolutionary development after all so (at least at some point) there exists a large market for this feature