Pretty sure it’s because both Apple and Google shave a commission off the top of any in-app purchases. So if you buy a subscription in the app, Meta would actually make less money. So to compensate, they increase the price for in-app purchases.

Alternatively, it could be because adblockers are less prevalent on mobile. Even casual desktop users have begun using adblockers, but very few people block ads on mobile.

It doesn’t need to be as dramatic as this. The goal is simply to obscure key parts of the face that are commonly used for individualization. Between the eyebrows, the bridge of the nose, jawline, eye tilt, etc are all common key data points that facial recognition systems use to differentiate between similar faces. You can also try to avoid facial detection from pinging you in the first place, by obscuring the expected oval head shape. Style your hair asymmetrically, have bangs that droop over one eye, break up the expected round shape, use a color that mismatches your skintone, etc…

Your face paint is definitely an extreme example of the latter. But the important part is that some may actually still be able to detect a face (even if it can’t positively identify them) because they didn’t do anything to obscure the head shape or obscure at least one of their eyes.