alt Hacker NewsYes, if your only device is a single Android phone you can do that. You can’t, however, use that backup to populate your message history on other platforms.
I’ve already lost message history consistency because one of my devices was offline for too long. The messages are there on my other device, but Signal refuses to let me copy my data from one of my devices to another. Signal is, quite literally, worse at syncing message history than IRC — at least with IRC I can set up a bouncer and have a consistent view of history on all of my devices, but there’re no Signal bouncers.
Look, if defending "message history consistency" is a reason you're choosing some other secure messenger rather than Signal, then I don't think this argument is very productive; use some other secure messenger then. But if "message history consistency" is a reason you're endorsing encrypted email over Signal, you're committing malpractice.
The point is that whatever secure messenger you use, it must plausibly be secure. Email cannot plausibly be made secure. Whatever other benefits you might get from using it --- federation, open source, UX improvements, universality --- come at the cost of grave security flaws.
Most people who use encrypted email are doing so in part because it does not matter if any of their messages are decrypted. They simply aren't interesting or valuable. But in endorsing a secure messenger of any sort, you're influencing the decisions of people whose messages are extremely sensitive, even life-or-death sensitive. For those people, federation or cross-platform support can't trump security, and as practitioners we are obligated to be clear about that.