I think the red asterisk just means that it is your comment.
Yes, the red asterisk is helpful for scanning a page when looking for your own posts or comments (although it is also possible to use any browser's find-on-page search, usually implemented as CTRL-F on Windows browsers, to search for your own username).
Offtopic, but: in case you need to reply to someone here, you can edit the text of your post within two hours.