I'm biased since I grew up with mm/dd/yy format, but I do find month first more useful simply because the 30-day period something takes place in gives me more c

I'm biased since I grew up with mm/dd/yy format, but I do find month first more useful simply because the 30-day period something takes place in gives me more context immediately about an event, at least when talking about scheduling things. The year is typically implied, so it's not needed. The actual day of month gives you more specificity, but the month is an easier "chunk" to keep in my head when thinking about a date. If I think about my next dentist appointment, just knowing that it's in September is more useful to me than just knowing the actual day of the month.