The United States has a rather unique way of writing the date that is imitated in very few other countries (although Canada and Belize do also use the form). In America, the date is formally written in month/day/year form.
They don't use metric, still use First Past the Post voting, elect a mini monarch with effectively unchecked powers, ... it's an odd place.
Also, the US military used/uses DDMMMYYYY format, i.e., 15JAN2025, where MMM is the month abbreviation, which is similar to one of the formats used in Romania. This has the benefits of unambiguous parsing and no need for component separators but lacks lexicographical sort-ability like ISO 8601. A format like YYYYMMMDD might some of the advantages of ISO 8601 by keeping items of the same year and month together at a minimum. (ISO 8601 is the most proper date format though. ;)
Mass shootings, out-of-control police, bankruptcies from for-profit healthcare and expensive medications, Bibles and Creationism in public schools, widespread ignorance about the world and just about everything, and millions (vastly undercounted) of homeless people.
But seriously, America is awesome for rich people if you don't mind living in a poor, third-world country that still believes it's a first-world, exceptional country.
That military style uses little endian so it belongs in the sane formats category.
However, with ISO you're likely referring to RFC3339. The full ISO8601 standard allows insane date representations you're not going to see anywhere but the documentation that explains them.
The only problem is that it puts the most important information last and the least important first (going by "what do I most likely need to see and cannot infer from context", ie I likely already know the year and possibly the month).