as a software developer who is constantly frustrated by ambiguous and confusing datetime representations, i'm really glad that your 24:00 display isn't in the spec. that's exactly the sort of thing that leads to bloated specs and programmers complaining about what a PITA dates are.

sure, your use case sounds valid. but that doesn't mean it needs to be part of the standard or implemented by everybody else. it's the sort of thing that should be implemented by the people who need it and that nobody else has to think about.