I agree. It seems to me that Facebook's Messenger and WhatsApp are fundamentally incompatible. With Messenger, you can open Facebook/messenger.com/your phone an

I agree. It seems to me that Facebook's Messenger and WhatsApp are fundamentally incompatible. With Messenger, you can open Facebook/messenger.com/your phone and see all your messages. With WhatsApp, you have no such option, as messages are not stored remotely. For the end-user, the most "seamless" way to integrate is to adopt Messenger's approach, which will be a security loss for WhatsApp unfortunately. As other users mentioned, there is also the possibility that the end-to-end encryption will lose its default status.