

Btrfs is a filesystem just like ext4, you can mount the root subvolume and upload all files somewhere.
Timeshift is not a backup solution though. Snapshots are built-in with btrfs. So you can install a snapshotter tool like Snapper. But it would be best if you already have partitioned you btrfs filesystem into multiple subvolumes. Like the suggested layout.





It really depends on the purpose. Sometimes you can hide stuff in unexpected places when there isn’t much interest for other people to find it, or if they don’t even know about it’s existence.
Also sometimes it is good enough to just delay the discovery of something for a while, because its value after a certain time diminished completely.
So, I would argue that sometimes security by obscurity can be useful. But I agree that it generally shouldn’t replace proper encryption.