It's common and easy to mount your host FS into the container, putting mutating data where you can take full advantage of the superior architecture and ops capabilities of whichever FS you prefer.
The images' internal AUFS/BTRFS layers are then only for keeping your binaries-at-rest and static configuration straight. They may as well be in highly indexed ZIP files, for all you care.
It's common and easy to mount your host FS into the container, putting mutating data where you can take full advantage of the superior architecture and ops capabilities of whichever FS you prefer.
The images' internal AUFS/BTRFS layers are then only for keeping your binaries-at-rest and static configuration straight. They may as well be in highly indexed ZIP files, for all you care.