Why would the year, the least important, need to be first?

Maybe it's not least important for everyone?

Almost like the preference can change depending on application...

If I'm looking at a folder full of spreadsheets, one each month (or even day) for several years, and they are all titled according to YYYY-MM-DD. All you need to do is sort by filename and now you have it broken down by year, into one spreadsheet per month/day.

And only needed to click one button to sort them into an easily readable format.