Your former examples are things that quite simply can’t be mitigated in any case. If you want to send a message to someone there is no way to prevent them from storing it in a way you control.
Your latter example is also a security concern they can’t address. A jurisdiction that allows a message about a settings change being used as a basis for obstruction of justice can rule the use of signal as the same (though I do agree that former is problematic on its face).
I dont know the ins and outs of the problems with backups, but it doesn’t take a phd in cryptography to envision a case where your settings about backups open all your contacts to automated dragnet surveillance. In that case it doesn’t make sense for a single user to downgrade everyone else’s security settings.
I'm not saying they can be mitigated, I'm saying that casual users have the illusion of security through settings that seem to mitigate security concerns, but don't.
The disappearing message timer history could absolutely be mitigated by simply not retaining that information or timestamping it.
If you could export/back up single conversations, you would have much more granularity than exporting or backing up your entire message database. Other people could also get a message that the conversation had been exported. there are lots of cases where you might want to do this by mutual agreement, but it isn't possible.
Your latter example is also a security concern they can’t address. A jurisdiction that allows a message about a settings change being used as a basis for obstruction of justice can rule the use of signal as the same (though I do agree that former is problematic on its face).
I dont know the ins and outs of the problems with backups, but it doesn’t take a phd in cryptography to envision a case where your settings about backups open all your contacts to automated dragnet surveillance. In that case it doesn’t make sense for a single user to downgrade everyone else’s security settings.