@dos2unix you might be interested in this https://fedoramagazine.org/btrfs-snapshots-backup-incremental/ turns out I wasn't completely wrong about the backup part, only it's not an automatic feature, you can however make incremental backups from the snapshots. An excerpt from the article:
And all of this without having to install anything else. That's pretty cool! By the way, when I said that snapper handles the whole snapshot process in openSUSE, that's not entirely right, you can handle snapshots with it but BTRFS does all the snapshot process by itself; create and delete them when necessary, usually it creates snapshots when the FS changes, .i.e. some mayor update, and it deletes old snapshots that are no longer necessary. Snnaper can do that as well, but it seems it's not really needed for this to work.Incremental backup
Another useful feature of snapshots is the ability to perform the send task in an incremental way. Let’s take another snapshot.
In order to perform the send task incrementally, you need to specify the previous snapshot as a base and this snapshot has to exist in the source and in the destination. Please note the -p option.Code:
sudo btrfs subvolume snapshot -r /home /.snapshots/home-day2
sudo btrfs send -p /.snapshot/home-day1 /.snapshot/home-day2 | sudo btrfs receive /run/media/user/mydisk/bk