They were the leader in incentive CPA industry back in 2009-2010 but they lost their first place when new competitors came like Adscend Media, Adwork Media and a few others. The 2nd major reason for the fall of CPA Lead was they handed the personal information of the publishers to several companies including Facebook. In 2009, the Facebook gold rush was on its peak, people were banking using Facebook apps + CPA Lead but the whole craze stopped when Facebook took serious action against those publishers and CPA Lead handed out all the information of the publishers. Then the publishers faced law suits, serious consequences and the most important money.
Upgrade to gold account thing is just an incentive to attract the publishers. Have a look at the email I received: