What would we gain by switching?
Maker Time is for people who build things, and building things requires decently long periods of focused time without interruptions.
But it also reminds you that time is passing and that you can not waste it.
It's the perfect clock for startup founders on the hack on product, eat, exercise and sleep lifestyle in an early stage company.
It's also weird if you start hacking at 2, and wake up the next day and start hacking at 1095.
Or 1098.
You have survived another rotation of the earth around the sun
and
It's time to close last years books and open a new set and deduct your business expenses against the new
Clocks count upwards precisely because time is infinite. When you count down, you're counting towards a finite point. The Gregorian calendar is already based on meaningful celestial events - a complete orbit around the sun and a complete earth rotation. And just like Maker Time, it resets every year.
Yes, you get this feeling of workable time periods, but we already get this with clocks. And with Maker Time, your periods are pre-defined: 12-8, 8-16, 8-24. if you work from 9-17 (like many people), Maker Time already encroaches upon two different periods.
Lastly, you can't realistically schedule anything, because an 8 hour window is too large to coordinate. It's a good attempt. I'm not just commenting to crap all over Maker Time, but it solves a non-problem.
If you look into the French Revolutions attempts to fit the 24 hour day and the 12 month year into units of 10, decimal time, they were much more unwieldy.