Uhm... well yes, you have to have one of the following:
1. Different time zones so you can know whether it's light/dark out somewhere.
2. The same time, but a location to know whether it's light/dark out somewhere.
But, even with #1, the actual lightness/darkness varies wildly based on location and season. Then there's cultural differences. In some countries, most people go to bed by 9pm, and in some countries most people stay up until much later, for example. When I worked at a French company, everyone was out by 17:30. In some other places I have worked, everyone stayed until at least 22:00 or later. - So again #1 (the current system) really doesn't help - but it does make the match annoying an mean that you constantly have to do conversions between time zones (including date), and ask people what time they meant.
If you did #2, scheduling meetings would be much easier. What time? 22:30 UTC? ok. done. That might be morning for you and evening for me, but if everyone agrees to it, you're good to go. There would be no BS like "Oh sorry I missed the meeting, I forgot Daylight savings time changed in your country on that day", etc.
The biggest negative effect would be that for the majority of people who interact only with local people there would be no immediate advantage, but they would have to get used to f.e. waking up at 22:00 instead of 09:00, etc. I don't think that would take that long though, it's just a number.