It's likely a simple case of following the money. Cost per action (CPA) ad pricing becomes a lot harder when you can't track people as easily, and that is likely a very lucrative ad format for FB.
Here's a good writup on the different types of ad pricing. There are a lot more features these days beyond clicks and impressions.
Here's a good writup on the different types of ad pricing. There are a lot more features these days beyond clicks and impressions.
https://blog.wishpond.com/post/74072092834/facebook-advertis...