Now Facebook wants to track other things that were out of their control too. If businesses start using the messenger, then facebook will know about my buying habits and other information too.
And how long will it take for Facebook to sell as Ads, the information back to businesses that helped them collect it.
How long then for FB to develop apps or acquire apps for the dominant use cases, and then squash out/limit the competing apps that integrated and helped build up the user behaviour to begin with? There's no way FB won't do this, that is part of their behaviour. How could they do this? They could all of a sudden require apps to use their payment, with whatever % taken that they please, and if you don't agree then they boot you and tell all of your users about their replacement app.
And how long will it take for Facebook to sell as Ads, the information back to businesses that helped them collect it.