3.2.a. A Persistent stream key means that you are using the same stream key for all your FB Live streaming events.
This is useful if you have several events on schedule via Zoom. You can use the same stream key when configuring Zoom. Facebook will automatically stream your event once it detects a stream coming from the stream key.
When this is disabled, you will need to configure FB and Zoom at the same time, each time you have an event to be scheduled live.