So there's less to think about. Its just a reorientation of what you remember - with one time zone, you only have to remember what time the sun comes up where you live. With times zones, you have to check stuff constantly if you travel. And time zones are already inaccurate because of political adjustments - look at a time zone map : they twist all over the place, and at least one huge country doesn't even use time zones - China is one single time zone. And Russia nuked two whole time zones recently. It increases logistical efficiency.

IMO it's inevitable. When a population is living in space, they're not going to bother with time zones. At some point, a billion people will live in orbit. Maybe a lot more. They're going to be reminding the grounders how tedius the time zones are every time they come down.