I think #3 is really interesting. As an advertiser with a lot of hands-on experience in ad platforms, FB from the start has tried to make the experience as simp

I think #3 is really interesting. As an advertiser with a lot of hands-on experience in ad platforms, FB from the start has tried to make the experience as simplistic as possible to manage. This has the side-effect of also getting less-savvy advertisers to spend lots of money on things that may be less effective for them, but may help FB's bottom line in terms of total advertiser spend and RPM's on their inventory by giving them greater control of where and to whom they fill a given impression in the auction. Depending on how things are working behind the scenes, I could see your third scenario being related to what I've observed. To be fair to them it's a tough Product situation. The majority of their advertisers are not savvy technical marketers who know the ins and outs of Ad Manager, have attribution solutions, etc. So in a sense, they need to overly simplify. But when you oversimplify things, require less technical setup of things like conversion tracking, etc., you tend to move further upstream from revenue-driving activity in the funnel, which can get very wasteful very quickly.