But then you have to unpack it, don't you? Like, diffs are great for downloading images, but once you've downloaded and want to run it, you still have to construct the final filesystem.
SquashFS is mountable directly as read-only. You can use Overlay just like Docker does to create a read-write layer on top. This combination of SquashFS+Overlay -- plus Xdelta3 for distribution -- has worked extremely well for the internal project I use it for.
