Sunlight is different everywhere. But not everything timed is tied to sunlight. There is no reason that the time should be 12:00 at peak sunlight locally.
UTC is an issue near the international date line. I could see residents of Pacific islands wanting to not have the date change mid-day. Should think about adding hours 24, 25, 26, etc. to Wednesday that are equivalent to hours 0, 1, 2, etc. on Thursday.
(And as a quant who did a lot of time programming for financial markets, fuck Daylight Saving Time and the leap second.)