How is affiliate marketing different/better than Google AdSense?
 

Obviously a mainstream topic here.

Ad networks used to be CPM/CPC. AdSense today is pseudo CPC but in fact it is a CPA network. The vast majority of advertisers have Google optimize their bids to maximize conversions which means your CPC will go up or down depending on how well your users convert.

So how come companies like commission junction exist? Why would I manually apply and select offers than track and optimize banners when AdSense does it for me and probably better?