Users may want to start with more than one presentation:

User story:
As a teacher, I am running BBB sessions with multiple presenters. These presenters send me their presentations several days before the session takes place.
As I like to prepare everything in time, I would like to upload the presentations into the BBB activity as soon as I have received and reviewed them.
Currently, I can only upload one presentation file per BBB activity instance.
As each presentation will be presenter by a different presenter, combining all presentation files into one file just to upload them into Moodle is more or less out of scope.

https://github.com/blindsidenetworks/moodle-mod_bigbluebuttonbn/issues/251