They do get to see the advertisement Theymos auctions off, but AFAIK, they pay a "flat rate" (so it doesn't matter if an advertisement has 1.000.000 or 5.000.000 views). Maybe it's interesting to tell a potential bidder for an advertisement slot that it usually receives x amount of views, and this "x" will be higher if you include those bounty users, but i doubt they actually generate much clicks (or revenue) for the advertisers.

An other thing might be that it has something to do with search engine rankings... A site that receives more daily updates might be ranked higher (i haven't done any SEO optimising for many, many years, so it might be possible that my SEO knowledge is grossly outdated).