I read once that the Spanish nightlife only starts at midnight. That makes a lot more sense if they are on Germany’s time zone.
If you're in a position where you're scheduling meetings you hopefully have some idea of where the participants are located and try to select a time that works for the most amount of people have woken up or not yet fallen asleep.
This will probably become more of an issue with more people working remotely though.
The UK, Ireland, and European countries east of the CET-zone are on different time zones, of course, but CET stretches from Serbia to Spain. That’s not as far as Shanghai to Tibet, but it’s still at least a couple solar hours.
Going by population density CET is probably far more disruptive though. The vast majority of the population that lives in EST is, by longitude, between Detroit and Boston, which is a narrower band than between Madrid and Belgrade.