GreengrassV2 StreamManager | KinesisConfig `start_sequence_number`

I'm using aws.greengrass.StreamManager v2.1.1 to export data to Kinesis.
In the KinesisConfig, I see a parameter named start_sequence_number, which has the following description:

param start_sequence_number: The sequence number of the message to use as the starting message in the export. Default is 0. The sequence number provided should be less than the newest sequence number in the stream, i.e., sequence number of the last messaged appended. To find the newest sequence number, describe the stream and then check the storage status of the returned MessageStreamInfo object.

When I read this description, my impression is that the Kinesis export will attempt to export all messages between start_sequence_number and the current sequence number. But I, joyfully, found out that even if I leave this parameter at the default (e.i. 0) the StreamManager knows the sequence number of the last exported message and picks it up from there.
Since it appears that the exporter has the intelligence to know which messages needs to be exported, I don't understand the use case of start_sequence_number parameter. Could you explain to me a use case for that?