Sounds like the main benefit is hash-based dedup. You can do this with ZFS and borgbackup - they'd likely be a better comparison - but most other compressed filesystems won't do it.

Most compressed filesystems will fail to dedup stuff because for various performance related reasons the compression window is usually quite small maybe up to 128kb and the files are often not sorted in the archive such that small files would manage to compress anyway in that window.

EDIT: Apparently squashfs does include file de-dupe however DwarFS is fixing what I basically said above. It sorts files in order of similarity so that you can compress accross file boundaries as well as just removing complete duplicates. That's pretty cool.

"Clustering of files by similarity using a similarity hash function. This makes it easier to exploit the redundancy across file boundaries."

This kindof thing is more difficult to do on a writable filesystem though not impossible.