I don't think Syncthing is the same. As far as I recall, it stores the full sync folder to disk, similar to traditional sync services. This project only stores a cache on the disk.
You are correct. With SyncThing each device gets a full copy of whatever folders you've asked it to sync there. The FUSE aspect of Zero lets it do just-in-time file transfer and have no solid upper limit on storage, saving bandwidth and disk space at the cost of portability, latency, and redundancy.
