Although the 12 hours aren't divided in day/night are they?
And depending on where/when you're at, it can easily be light out at seven and seven, even in the same day.
What the 12 hour clock does well is to track when the sun goes up or down relative to the only convenient time marker: midday. It also does so in a pleasingly symmetrical way: it gets light and dark at about 8, rather than 4 hours before and 8 hours after midday.
I'd argue if you want to track time, rather than record the ends of daylight, a linear scale for the whole day makes more sense. If it should be reset daily or not, be divisible by 24, 86400, 100, 1000000, a second or whatever is mostly a choice of convention. If you have constant access to a clock, Internet time seems convenient, for humans without clocks we use daylight and units like hours and 5-minute increments.
For that the 24 hour clock seems simple and convenient, although it would be nice to be able to calibrate without a watch (is it two or three hours before midday? How many more hours until wake-up time?). 24 hour time isn't perfect, but it's much better adapted to modern life than the 12 hour clock.
