When you offer an incentive to someone to click on an offer, they are really clicking on the offer in order to get the gift you are showing. This means that they are not really targeted traffic, because they are not interestd in the offer they want the gift. Some CPA companies allow this traffic because their sales funnel can convert this traffic, or they believe it can.
Most CPA companies see this traffic as not converting very well, and only want people who are interested in their offer to click on it.
When you give a gift, it is called an incentive, because you are using the gift to bribe the clicker into completing the offer.
Suppose I put a IM graphics package that I sell into a content locker. If someone wants the graphics, they fill out an offer, and they get the package.
More than likely, they are not interested in the offer and will not become a customer to the advertiser of the offer.
They wanted the graphics, and they only jumped thru the hoop because you required them to jump thru to get the goodie.