What makes MDY special is that it is worthless even with its normal context yet still widely used.

Those you mention make perfect sense in context: %C is usefull for historians (would you rather be parsing roman numbers?) and %h%m is good for voice radio transmission. Ideally you want to tag a format so that you have context, but I guess that's a bit difficult to do without introducing localization. It's somewhat akin to the issues with less common script in Unicode - yes, those are somewhat weird, but they do have a purpose. The standard tries to encompass every usecase rather than take a YAGNI approach, which is a sensible (if opinionated) thing to do.

On the contrary, MDY would appear in the same context you would expect DMY or YMD. It's only supposed advantage is that it maps English word order. But it is unsortable without parsing.