For 10 posts a week (or less), I don't find it significantly impact junk post because we will get 10 posts anyway except really busy IRL. The real danger is when the campaign demand more posts and/or stakes based on post counts.
You would think that people getting paid to post would at least take some time in their replies and make a thoughtful post. But, it's just too easy. The criteria is way too low, and I do understand that the more people, and more posts the better advertising. But, if it were me who brought out something worth advertising I would want to best quality posters rather than hiring a bunch of Jr Members who have only ever posted in off topic and spam megathreads.