What are some clear benefits of running master/agent configuration management? Ansible seems to have a clear advantage over competition like chef and puppet because it is agent-less and saves a certain degree of overhead.

I have read several comparisons of the various configuration tools and while each tool has its own strengths and weaknesses, I realize that much of it is down to personal preference.

The benefit of being agent-less is a no-brainer but are there any advantages of the master/agent architecture with respect to configuration management tools?
I've found an interesting discussion on the topic configuration management pull vs push topology

One contributor writes that pull systems (master/agent) offer more flexibility and are easier to scale.