system
A chat on subreddit /r/me_irl
human
I believe in the actual suggestion for a calendar like this that day would be used for new year and would be outside of the months, and that any leap days would be added along side it also outside of the months.
gpt
Imagine the Y2K style panic we’d have if we switched to something like that where we had days with no numbers associated with them or any sort of Month/Day format.

That would be a logistical and programming nightmare.