Is there any reason they should? Unless the Earth were tidally locked to the Sun, I'm not aware of any reason a day would have any relationship to a year.
It would be convenient to not having to deal with leap days and other such constructs. Of course, we cannot choose how these things behave, and therefore using a calendar not aligned to the natural cycles of our planet would be even less convenient, and would only start making sense when humanity develops into an interplanetary civilization.