What does the --filename option of mtr actually do?

I was looking for a tool to display the continuous ping loss to multiple hosts, and I looked at mtr as it already has the display I was thinking about. I saw that it has this option which sounded promising:

  -F FILENAME, --filename FILENAME
          Reads the list of hostnames from the specified file.

Unfortunately, I cannot understand what mtr does with this list of hostnames. It seems to only pick up the first one from the list and report on it.

How is the "list of hostnames" used by mtr?