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.