Gregorian calendar is a total mess. Few on this planet have implemented
it properly down to single second. Additionally the local time in it is
political decision that changes from year to year. So one needs database
to find out what wall clock did show at time of certain event few
years ago. I guess Boost.Date_Time for example is still defective. It
sure was when I last tried it out of boredom.
The chrono just tries to make Gregorian calendar a bit less pain to
use but grisly aspects of it are still there. Also it likely does
not link stuff that you don't use into your program (unlike
Boost.Date_Time did).