I have read the actual ISO 8601 spec. It is somewhat typical wall of prose ISO standard that contains meaningful conformance distinctions which depend on two wo

I have read the actual ISO 8601 spec. It is somewhat typical wall of prose ISO standard that contains meaningful conformance distinctions which depend on two words in the middle of 10+ line paragraph. For me, more significant reason to prefer RFC 3339 constrained profile is that ISO 8601 does not only mean YYYY-MM-DDTHH:MM:SS.sss but also includes bunch of alternate syntaxes like YYYY-DDD. And I have one big issue with RFC3339: there are cases when the "don't care about timezone" ISO 8601 syntax is actually useful.