If you're seriously worried about that you're already using disappearing messages, and the maximum retention period is 4 weeks. It's good that they're doing this but it also feels a little bit like hype, while very basic UI problems remain unfixed.

For example, you can do backups or media exports from signal, but the user isn't given any control over where they are stored. If you want to dump them to an SD card in your phone, for example, you'll have to find them in your primary storage and then copy them manually to the SD card. Bizarrely, voice messages are dumped into a 'music' folder even though they're labeled as 'audio' within the Signal UI.