I don't think rounding clocks would be any more useful in the scenario about mentally calculating how many minutes until the meeting at noon, because a rounding

I don't think rounding clocks would be any more useful in the scenario about mentally calculating how many minutes until the meeting at noon, because a rounding clock would show noon 30 seconds earlier, so the average difference between 11:55 and noon in a rounded clock vs a floor clock is still 4.5 minutes.