Attachments to a video event

Let's assume that there is a video event platform. When a host creates an event they can attach some files to it. These files are stored permanently for all the participants even after the event ends.

There is another type of files which exists when the video event takes place. They are temporary and to be removed when the event finishes. It's like live chat of files during the event.

The question is does it makes sense to save files from the live chat and attach them to an event? Should it be made automatically or it's better asking the host to attach each separate file?