i just think it better to show someone content first at least they know it is something they want higher chance they will do survey,but buying traffic may or may not work too well for cpa now u will need targetd traffic or ppc
why anyone would do the survey unless they knew they want the grayed out content? I can sell you traffic that is good for freebies, make money, marketing, etc niches, but I am not sure you will be able to convert any with a landing page like this