Only queues for which the user has this right will be listed on the "Customize Quick search" page, which in turn allows them to be displayed in the "Quick search" section on the "RT at a glance" page.
This right can be granted to users and groups on a global level or on a queue-by-queue basis.
A note on the "Quick Search" section:
I'm adding this note because it was a headache to figure out. Hopefully I can save your aspirin bill
When you grant ShowTicket and SeeQueue permissions to a user or group to see a queue in the "Quick Search" widget, then the user has to log out and log back in to see the queue in the list.