just to add as dates annoy the crap out of me, YYYY/MM/DD is the ISO standard for the world. Most if not all databases stores dates in this format, going from the largest to the smallest similar to the actual decimal system.

But yes as I said earlier it makes sense as a UI when you look at it, especially if you are using a gamepad left goes up in decimal right goes down. up goes up in number on the decimal highlighted, down goes down.