Its actually useful in a thin client environment that it does. And the user can configure blanking easily enough
True, though I think xcreensaver should be off by default under vnc.
Because to ship screensaver output over vnc takes a lot of CPU and network resources. IMHO this should not happen by default, because newly setup machine with a few users running vncserver hammers the machine. If they want to setup screensavers explicitly, fine, but at least you can lart them for that :-)