A distro can make automation more difficult than it needs to be. As I mentioned in my examples, Preseed sucks, have you ever used it? And of course Ansible works on pretty much any distro, but Debian family distros are made with the expectation of user input, such as expecting configuration values during package installation and this has to be worked around. It's not impossible, just more work and testing. When you're automating CentOS and Ubuntu next to each other, you'll realize extra Ubuntu related code.
Not a big deal, it's just minor preferences.