As one HN comment said years ago: I feel leap seconds have always lived in the wrong abstraction layer.
They should live in the same abstraction layer that does leap days and daylight savings: the time zones.
The changes in Earth's rotational speed that leap seconds help account for affect the whole globe. Why shouldn't the effects be noted in the global time standard?
god that would be awful. Can you imagine time zones being one second off from each other. Or two or three? ah yes, india is GMT+4:30:03, where europe is GMT+0:59:58
Leap days, February 29th, are not at the level of time zones. Different time zones do not disagree as to when March 1st will occurs immediately after February 28th.