If you didn't have it the error message would be
xhost: command not found
gh-1057:/home/invasian # xhost
Xlib: connection to ":0.0" refused by server
Xlib: No protocol specified
xhost: unable to open display ":0"
Your error message means that a) you're either not
running X at all or b) trying to start xhost as another
user than the one who started that particular xsession.