AppFS is built on FUSE just like SSHFS, it just uses a different transport protocol, doesn't support pushing writes back the origin server, does heavy caching,

AppFS is built on FUSE just like SSHFS, it just uses a different transport protocol, doesn't support pushing writes back the origin server, does heavy caching, safely supports multiple users (including writes), can safely connect to untrusted servers (uses end-to-end PKI, so verification works even if the original URLs are not the same for example if mirroring is used), and handles setuid-root files in a safe way.