WhatsApp had some real issues and then it seemed they cleaned it up. It seems every mainstream researcher now agree that the message delivery part of WhatsApp

WhatsApp had some real issues and then it seemed they cleaned it up. It seems every mainstream researcher now agree that the message delivery part of WhatsApps is now trustworthy. That said the metadata and incentives story is about as bad as it can get[1] and in the backup department your chats can be uploaded wholesale to iCloud and/or Google Cloud if one of your contacts from the same conversations enable cloud backup. [1]: Owned by Facebook and they shut off the revenue stream so the only way they can make money from it is by squeezing it of the metadata they get or introduce ads.