A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Date: 2016 Dec 30, 08:26 -0800
As I see it, the conflict arises between two different "customers" for time.
Customer one wants to know what time it is with respect to the celestial sphere, most importantly the sun. Keeping the sun's meridian passage near 12:00:00 at the reference meridian requires leap seconds; keeping the equinoxes in place requires leap years. UT1 and UTC work for this customer.
Customer two wants to know how many seconds (and perhaps fractions thereof) have elapsed between two events; or conversely, to be able to unambiguously timestamp events and to sequence them. Leap thingies are antithetical to this. TAI and Julian Day Number work for this customer.