Нужно, например, для хождения по папкам, куда пускают только с правами root. И для drag'n'drop.
При
su
caja
Получаю:
(caja:4544): Unique-DBus-WARNING **: Unable to open a connection to the session bus: Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken.
(caja:4544): Unique-DBus-WARNING **: Unable to connect to the running instance, aborting.
(caja:4544): Unique-DBus-WARNING **: Unable to open a connection to the session bus: Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken.
(caja:4544): Unique-DBus-WARNING **: Unable to connect to the running instance, aborting.