You already have to ensure virtual meeting participants will be awake. What disappears is the research and lingering doubt about when the meeting really will be in everyone's local time this week.

If you're confused about when your friend woke up, that won't make you miss a meeting/phone call/WoW raid.

This is already a real problem, and the more we interact with people in other time zone in our ever more networked world, the bigger it will become.