I've used this feature only once so far.  It might turn out to be useful for
running Pd on PDAs and such.

...and XBOX'es. My XBOX is happily running pd, pdp, webcam input, audio
output and fullscreen tv pdp output, without a keyboard or mouse attached,
while the gui is on my desktop. Running X across the net is also possible,
but less efficient I guess. And I'd get the pdp output at the wrong
display.