Honestly, I think they just saw that Whatsapp was becoming the standard chat app for basically all of the world outside of the US and China, and just didn’t want anybody else to have it.

Additionally, metadata is better than no data, I guess.

The metadata. The message content is E2E, but the data about the content isn’t necessarily e2e.

If you go only by the metadata, they know all your friends, their phone numbers, your location history, when do you chat, with whom, how often and how long. And I’m fairly sure they index conversation in some form.

Just location history can paint a decent picture of what you do, where do you go, what do you like, which friends are nearby, etc… and all of that was implemented like 15+ years ago, imagine what they can do today with AI. It’s fair to say FB knows more about you then you do (FB, IG, Wapp…). And to be blunt, it could probably determine what ppls shit smells like, judging by all the pictures of a meal they post on IG.