For example,
60 seconds = 1 minute
60 minutes = 1 hour
24 hours = 1 day
7 day = 1 week
29-31 days = Month (approx.)
365/366 days = year
It’s like for the imperial measurement of distance, where 1 mile = 5280 feet…
Edit: just to clarify, I’m more or less keen towards any consistent, decimal-based measurement systems like base-10 or base-12.
12 hours in half a day is fine for me. 12 can be divided into halves, thirds, quarters and sixths. That’s useful for planning out a day. Time is one of the applications where I don’t have a complaint about using base 12.
The real confusion is when you count the days in a month, or year…
Exactly why there are 12 months and 24h a day, for easy divisions.