It's a fantastic idea!
Why continue with the complicated and absurd Gregorian calendar? With this calendar every month is the same and every day of the week will always have the same date. It's over having to think about what day of the week you live:
This month is ending, is it Monday or Tuesday? In ten days, will it be a holiday?
It has 3 days (4 in leap years) outside of the months that can be converted into holidays without having to mismatch the monthly plans, as the months continue to be the same.
Not being able to divide it into quarters, nor quarters or anything, since 13 is a prime number. Although I think this is a salvageable obstacle.
Start the week on Sunday. Those who come from countries with a Catholic or Orthodox tradition are accustomed to starting weeks on Monday and finishing them on Sundays. In addition, if done in this way there would be no Friday 13 ...
So, I think this calendar would help a lot. I know it can be very difficult for some because the rhythms and times to live are implemented since we are very small but the time has come to change. WE CAN NOT FOLLOW THE SAME!