[zeveb]

One of these passwords, if they truly are sufficiently-secure, could be used to secure a password manager's encrypted file at rest on a system outside of one's own control.

Right now, the best guidance is to only use a memorable password on files which never leave one's physical control, and to use truly-random passwords on remote machines. This is a pain, because it means that one cannot (or at least, should not) back up one's data securely: any encrypted backup would require a password under one's physical control, but the whole point of the remote backup is to recover from incidents compromising one's physical control. It's a conundrum.

This development could be of real use in securing a remote backup of one's passwords: high-entropy and memorable.

[eridius]

Encrypt your backup using a secure password that's stored in the backup (in your password manager), and then just have a physical copy of the password stored in a fire safe, or safety deposit box, or something else of that ilk. As long as you haven't suffered catastrophic computer loss, you can recover your password using the password manager. If your house burns down with all your stuff in it, you can use the physical copy to access your backup (or, ya know, some other mobile computing device like a laptop or smartphone that also has access to the password manager).