If you are deploying anything reasonably complicated - you HAVE to. Now, I quite like my config files but there's no denying that they are more complex then GUI utilities for a lot of people.
Another story (I have tons of them) from my Linux deployment experience. Situation: company's managers want to control access to Facebook and similar sites, allowing unrestricted access to certain groups of users. Their current solution is Kerio Firewall (actually an HTTP proxy) on Windows Server, it allows to edit access lists using a simple GUI tool (translated into Russian, btw).
I've tried replacing it by transparent Squid but there are NO solutions that provide necessary functionality. There is a couple of commercial ISP-oriented packages that require dances with shaman's drum around them to make them work, and still they are not enough.