I've certainly used this feature in the Debian installer to create Xfce and LXDE systems, and I'm looking forward to doing it with the Fedora installer in the future. (Disclaimer: I did my recent Fedora Xfce installations from the excellent live media that are part of the Fedora Spins portion of the project.)
I love both of these distributions, Debian and Fedora, even when they frustrate the hell out of me. If that doesn't come through in all of this writing, I humbly apologize.
Linux Shell is one of the most fascinating and powerful GNU/Linux powered tool. All the application, including X, is built over shell and Linux shell is so powerful that the whole Linux system can be controlled precisely, using it. The other aspect of Linux shell is that, it can be potentially harmful, when you executed a system command, without knowing its consequence or unknowingly.