See, at the end? What you’re describing is timezones with a different name, and more fine grained so we have more of them. This makes it harder.
Business hours are correlated to where the sun is, which is why I used the sun as a stand in for “how people progress through their day as mediated by our biological day night cycles”.
People communicate with people in parts of the planet where everyone would say it’s a different time because the sun is in a different part of the sky.
Lumping places together by rough sun position is better than every town keeping their own time.
Jumping through hoops to avoid saying that our sense of time is linked to the location of the sun in the sky is just making things more complex than it needs to be.
Again, we already have UTC. People use it where it makes sense.