Useless in what sense??
Isn't he getting backlinks from 20 sites? (Maybe some with high PR?)
In my opinion I think Rob Whisonant said it right.
IF the article directory is willing to publish that duplicate content, why wouldn't you get the backlink from that directory?
BUT, let your content be indexed by Google first on your site, if the content is for a keyword you are targeting.
I would wait a few days and even send a few backlinks so G knows I'm the original source for that content.