The first one is to split a batch of something: there's more ways to split 12 of something than 10 of something, but you can use base 10 and still do things in batches of 12.
The second reason is for easy divisibility checks, but for that all that matters is prime divisors. Base 12 and base 10 have the same number of prime divisors 2 and 3 versus 2 and 5. But base 10 has an interesting property here, because 10-1 is 9, which is a power of 3 you get somewhat easy divisibility rules for both 9 and 3. 12-1, on the other hand, is 11 which is prime so you only have a relatively uninteresting divisibility rule for 11.
I think at best you can claim that 12 is about as good as 10. Base 60 would be strictly better than base 10 if it weren't for the fact that we can't easily memorize multiplication tables for base 60.