IT matters when you have an economic zone in which some have 9am being 'basically mid-day', while the others have '9am being 'oh, the sun just went up'.

This traditionally has been solved in two ways:

1. do the split and accept that you will have costs associated with different time zones and sleep/wake cycles in your population (e.g.: USA / Soviet Russia)

2. don't do the split, and have the cost by putting a time/light adjustment burden on the population (e.g.: PRC, European Union)

My preferred solution would be to abandon all time zones and use something like UTC, or yet better: .beat / Biel Mean Time [1], which does not come with a 'oh, 12 means midday' penalty.

[1] https://en.wikipedia.org/wiki/Swatch_Internet_Time