The mystery of having DVD drives in server systems

There is one mystery that eludes my understanding: Why does so much customers insists to have optical drives in their servers? Okay, when you have only one server, it makes sense. But for customers with dozens of them in all forms and colors of Sun equipment they doesn´t really make sense. You simply don´t need it. For installing you really should use jumpstart, no need to boot the system via DVD. It´s really easy in configuration and usage. And as i´m lazy i don´t want to walk into the datacenter to change the disc I generate an .iso-file with dd on my workstation and put it onto a fileserver. Whenever i need it, i mount it with a similar procedure i´ve described in my wiki to integrate new Opensolaris releases to my Jumpstart environment. And since all modern server have Gigabit Ethernet onboard, using the network gives you a reasonable speed to access your central files. This .isos can´t get lost. You don´t have to search your colleagues desktop for the installation DVD´s of a product. The .isos can´t get scratched. So can anybody explain me, why still customers insists of having DVD drives in every server they operate?