While self-moderation has the benefits Jet Cash mentioned, it is almost exclusively used to curate feedback and scam other users. I think one possible solution would be to restrict the self-moderation ability to only Members+, as this would at least stop the most flagrant abuse. Something also needs to be done about auto-buy links (selly, rocketr, etc.), these are just as much a plague in the Digital Goods section.
It a great idea, however I have suggested numerous times here to either not allow locked or self-moderated threads AT ALL in digital or limit to full member and above. Each time I got shot down with "people should be able to take care of themselves" (or similar).