[_delirium]

I can see that for some kinds of admin tasks, but why package management? At least on Debian, the package manager is already declarative: There's an install/upgrade planner that figures out how to get from the current system state to the final desired state, given constraints such as packages' declared Requires/Conflicts/etc. lines. If the system is already at that state, it does nothing.

[weaksauce]

How often is setting up a package just running apt-get? There is an overwhelming majority of times where you have to change something in the config file somewhere. Ansible can do anything you want to provision your boxes.