Having an option to automatically backup the app’s data. Ideally incremental backups that are updated when anything changes (for example when you receive or send a new message).
Right now a backup needs to be performed manually and entirely each time.
As long as backups are not encrypted by default, I think it is best to continue having to run them manually. In any case running incremental backups for every single message seems excessive to me, in the end if you don’t want to lose the messages you can keep them on the server.
One could make it an option to do it that way, or set specific times to do it (like once a day). I do agree however that encrypted backups should be higher up the priority list (although users could do this themselves too).