I understand why everyone's instant reaction might be "good," but if you are in the business of making an app, you will eventually need to get users for your app. Advertising is how that happens. That's because app store discovery was nerfed years ago, to make store search ads a revenue source. This Apple IDFA change will likely force you to redirect your ad spend from the Facebook Audience Network to Apple search ads.
No, Search Ads is keywords targeting, not "we build a whole profile of you and then use that". It has its own issues, but they're not the ones you have with Facebook's solution.
Except you don't get people buying fake ovens offline. There isn't a great analogy I can think of but there is a huge amount of ad fraud where it's profitable to fake an install, fake app use to generate more fake ad revenue ad fake installs, etc. So long as it's profitable for someone to fake installs and fake user traffic there will be a need for better value conversion tracking
