You’re assuming that everyone’s schedule follows the sun the same way. People already have different time of availability because of sleep schedules. Without time zones you wouldn’t have to do the additional step of converting times or asking their time zone or being caught off guard because you didn’t know their country went to DST already.
‘Are you available between 10 and 16?’ vs ‘Are you busy tomorrow morning? oh tomorrow morning my time, uh like in 10 hours’
I really want to hear the room chatter that was happening 5 minutes in. Surely after like 15 the sorts of people there would have been like ‘ok we’re vibing with the supreme leader listening to music, this is cool too’ but after 5 minutes there had to be some confused discussion that would be really funny to hear.