This way certain directories could be mounted read only (i.e. reside on a read-only partition/disk). Some directories were supposed to be governed by the core d

This way certain directories could be mounted read only (i.e. reside on a read-only partition/disk). Some directories were supposed to be governed by the core distribution, some were for user-installed software etc. It makes sense given the original intentions & restrictions. It may look weird on a one-person working station.