Well, ofcourse CTR is important - because if the CTR is 0% there will be no sales
Some stuff can be sold be aiming after a high CTR .. the effect will be that alot of users who really wasn't going to buy do it anyway..
On the other sites - metioning the price of a cheap trial will make alot of the people who thinks paid porn is always expensive to sign up - but these link have a low CTR