If you regularly encounter humans that use different date formats, IMO that method is a great way to avoid confusion between dd/mm/yy and mm/dd/yy.

ISO-8601 is great for computers since it has nice sorting properties, but IMO it's less great for human to human communication. For example if you're trying to set an appointment (or reading current news), it wastes a lot of time to specify the year for every message or article when it's already clear from context.