If you get rid of time zones, people will replace them with an ad hoc system that does most of the same things but worse. The current implementation could be improved some, but time zones in general are close to the least worst option.
I think having a unified time everywhere is a really obvious advantage. Time being measured differently based on geographic location is completely silly. You would still need to look up how a different location is scheduled but you also need to do that with timezones so there's no disadvantage, only an advantage.
I mean each city used to have their own time zone and we got rid of that.
The next step is to just get rid of the country-sized timezones. Sure the sun doesn't rise in US West as US East at the same time but it also doesn't rise at the same time in Florida as it does in Maine.
If you get rid of time zones, people will replace them with an ad hoc system that does most of the same things but worse. The current implementation could be improved some, but time zones in general are close to the least worst option.