It's not just good for developers. Coordinating any plans across timezones always requires the timezone to be explicit, one universal timezone doesn't. It wouldn't be hard at all for people to get accustomed to the numbers associated with their local daylight cycle, and travellers can use a phone or website to lookup sunrise/sunset in any location, as is already possible.

Maybe we could even eliminate hours and minutes and just use percents and thousandths of a percent of a day (14.4 minutes and 864 ms respectively), to avoid factors of 60 or 24 or 3600 or 1440.