I guess one could do it date-month-year, but that’s a lot of extra work ... date, now wait for the month before it has meaning, now wait for the year before the month has meaning.
YYYY-MM-DD seems more natural for me. I Understand you thought process (I think) about sticking with a unique format it can be applied to a lot of things, a good example of that is the metric system. But we all know that there will be always a few people who won't change, like the US who is sticking with the imperial units. Or The Problem with Time & Timezones: https://www.youtube.com/watch?v=-5wpm-gesOY
@lnxw48a1 One of the best things about ISO 8601 (compared to DD.MM.YYYY) is that it is consistent with the time notation as well: YYYY > MM > DD > hh > mm > ss.