If only people would be less set in our ways, you could use the same calendar every year:
( ) having one or two days per year which are part of no month is stupid
( ) having one or two days per year with no day of the week is asinine
( ) social constructs are actually very important
https://en.wikipedia.org/wiki/International_Fixed_Calendar
I find it much more compelling than World Calendar, although ultimately I think switching calendar systems is not very practical at this point.
I had not seen it, so thanks for sharing!
Also, relatedly and less personal, holidays like July 4th would always be on a Wednesday, which is a terrible day to have a statutory holiday. There is a reason that the holidays that are defined by their day of the week always fall on Monday or Friday (with Thanksgiving being the exception, but the Friday following is almost always a holiday for most people).