IMO, as a huge amount of information of user behaviour (scrolling time, post viewing time, clicks etc.) is collected from the frontend apps, losing that kind of visibility is a no-no for them.
This also explains app size, IMO. Querying an API and displaying remote videos/images should not require 40+ MiB Android apps. I think most of the app size is the tracking code that analyze how much time you glare at ads.