According to the discovery by WABetaInfo, they write, “Following the references listed in this image, Facebook can understand if a WhatsApp contact is blocked, sounds of push notifications, the details of a chat (that includes particular information like the phone number of the contact, a message counter, if the chat is archived..) but not its content, members of a specific group and profile pictures of the contact.”
While there is no explicit mention of cross-platform messaging, their discovery does seem to suggest that Facebook could potentially be laying down the groundwork to make that happen. If this is accurate and Facebook is planning to do what we think they are planning to do, it could actually be a pretty good idea.
This could reduce the number of messaging apps we may need, making it more efficient. However, there are also some privacy concerns since WhatsApp uses end-to-end encryption, while Messenger does not. In any case, it might be too early to tell, but in the meantime what do you think? Would such a feature be of interest to you?