Sadly, the 100 day year never worked quite right.
Also, the months were given names by a Poet, and the days had minerals, vertues or plants instead of Saints. The calendar itself was pretty cool.
Honestly, if they had 5 weeks of 6 days each instead of the 3 weeks of 10 days, I'd even call it the perfect calendar.
60 can be split into 2, 3, 4, 5, 6, 10, 12, 15, 20, 30 evenly for example
The other number that accomplishes this is 12: 2, 3, 4, 6 are all factors.
That's why 12 and 60 are so common for real life systems.
There's an argument for 12 for sure, but I still think having a power of 2 would be more beneficial than having the extra factors. 8 would give you the same number of integer factors as 10, plus all the benefits of being a power of 2.