Only root can run xconsole. Other users get "Couldn't open console" in the xconsole window and no output. ppp.txt recommends using xconsole to display daemon messages. It is very handy for watch the login progress, or lack there of.
Configuration issue - you have to be able to read from the device, and most likely /dev/console is only readable by root. You can pass alternate files/devices to xconsole with the -file option.