Facebook now has the concept of both private (i.e. e2e encrypted) and temporary conversations. The UI to access them is a big awkward to be sure. That doesn't

Facebook now has the concept of both private (i.e. e2e encrypted) and temporary conversations. The UI to access them is a big awkward to be sure. That doesn't help the problem of old messages from before these existed. It's also not super helpful because the retention is no more than a day. Better I think would be like a year -- enough time that you're unlikely to want to refer back to it.