This is super neat. Some micronation or fictional paracosm should adopt it and popularize it.
I and a friend or two years ago, hacked away at what we were calling a metric-calendar. Which was insanely impractical, but we were trying to achieve a similar sort of calendar symmetry/order.
We had at some point worked out a fictional holidays around when our calendar would synchronize with the current real world calendar, and when it was at max desycnhronization.
Tangently related: I’ve been reading the Kim Stanley Robinson Mars trilogy, and the time keeping they do for Martian time is pretty interesting in it’s own right.