Whoever thought supporting sexagesimal numbers was a good idea needs to spend some extended time away from their computer to reflect on what they’ve done
That makes sense, but I think the vast majority of tools that need time values would actually expect users to just input a string and parse that themselves.
IMO anything other than the basic types supported by JSON (number, true, false, null) ought to be be parsed as a string. Or if you really insist, some kind of special syntax to make it clear it's not a string would probably be acceptable.
We wanted a file format that's easy to read and less verbose than xml and all we got was something that is so full of pitfalls that it would be easier just not to use it.