Hiya,
Yes I would agree it doesn't cause harm however it doesn't do anything else either. The canonical doesn't make a difference really. I wouldn't see how it protects you from scrapers or people stealing your content having your page indexed first is irrelevant of the tag. look at it another way if a scraper stole your content they could just stick a canonical pointing to them selfs and thus claim it was their content, it wouldn't work. It all boils down to who Google index's to and if most people are pointing to the original (in theory)
Reason I pointed it out was it may have been an error of Google getting in a muddle with the canonical and might of been worth a try 