Some people are sceptical that Mark Zuckerberg truly intends to shift Facebook's focus to private, encrypted communication.
I think we can take Zuckerberg at face value here. Product-wise it implies a shift in direction and a lot of work. But it doesn't require Facebook to alter its core business.
Whether users communicate publicly or privately with Facebook's products, the company will still have access to vast amounts of data on every user to sell ads against. And it won't necessarily change how un/ethically they use it. This wouldn't have any impact on, for example, using 2FA phone numbers to target ads at users. Or whether Facebook's algorithms promote clickbait conspiracy content because that's what people engage with.
Coincidentally, it sure helps them make the case for integrating Messenger/Instagram/WhatsApp.
There may be some positive changes that come out of this, but for the most part it seems like business as usual.