Video conference 'waiting rooms'

Waiting rooms add an extra level of security and control to Zoom meetings. How have you used these? What are the advantages and disadvantages of waiting rooms? Do other platforms have comparable features?

For some context, here is the guidance we offer on using the waiting rooms in Zoom.
https://docs.carpentries.org/topic_folders/communications/tools/zoom_rooms.html#creating-a-waiting-room