Can this device function as an SSD, holding, for example, a Keepass2Android APK file and a KeePass database -- as well as being able to open said datanbase via one of the stored profiles? It doesn't need to have a lot of storage... 640 MB ought to be enough for anyone's KeePass databases.
I use KeePassXC on macOS, Windows, and Linux and copying the database to the machines in question is easy enough. I was specifically thinking for iOS and Android without going through iCloud.