This diagram is dumb, if we read it from the top as you normally do with text, without context you could easily end up writing dates like this:

59:59:23 - 31-12-2025

instead of like this (which I agree is the proper format):

2025-12-31 - 23:59:59

EDIT: Isnt America’s diagram wrong, if we only look at the date portion (and ignore the AM/PM idiocy), don’t they tend to write

Month Day Year - 12/31/2025

not

Year Day Month - 2025/31/12

Or RFC3339, which is freely available unlike ISO.