[uv-depression]

Do you also think it's "strange" that they're introducing that (optional!) feature while also storing all the messages on your device? The cloud backup is strictly more secure than that on-device database. Their blog post on the subject also explicitly says it won't include disappearing messages that disappear within 24 hours.

[elvisloops]

It's not optional because you don't know whether the people you are communicating with have it enabled. One person in a group chat with the feature enabled undoes the forward secrecy for everyone in the group chat.

A cloud backup eliminates any forward secrecy. It used to be that in Signal, when you have a message on your device and it is deleted (or a disappearing message disappears), then it is truly gone and can never be recovered. Now with backups, since the key that was used to encrypt it to the cloud remains on your device, it can be recovered even after the message is deleted or disappears.

The only way to "truly" opt-out is to, as you say, set a disappearing message timer for <24 hours.

[uv-depression]

Yeah, and all of that's already true right now because messages are stored on those users' devices already. You'll be heartbroken to hear that those users can also take a screenshot of your disappearing messages and send it to anyone. There are fundamental limitations to what a messaging app can protect you from.

[pluto_modadic]

this is the same argument as saying "you shouldn't have remote delete requests". Yes, people can screenshot or export. That doesn't mean you shouldn't have a nicety that generally works pre-compromise or pre-evil. Locks just keep honest people honest.