@th_in_gs same here actually. macOS uses something similar, called signed system volume. On linux you can still layer packages on top (although i wouldn’t recommend it as first step) and the nice thing: it’s blue/green booting. So updating the system is just downloading a new set of layers (which form a new “deployment”) and next reboot boots automatically into it. Problems? Just reboot and select the previous deployment. You can also view the pkg updates like a simple diff