For the tiny fraction of people who do not trust their local network, UrBackup allows running the connection in Internet (encrypted) mode. (I use it for a system behind a relatively slow WiFi link, as this works a bit better for me.) There is an enable_internet_only.bat in the Windows client program folder - should be something similar in the Linux and MacOS versions. Look for other posts here that discuss this subject.
Excellent compression is achieved by the standard deduplication features of UrBackup, where identical files from single or multiple clients are stored only once. You could run 10 full backups a day, and if nothing changed it would only take the space for the metadata needed to account for that fact. The actual files would be saved only once - which can greatly reduce network traffic. Also see the Documentation and discussions of ZFS and btrfs for additional storage reduction techniques. The optional change block tracking for Windows can reduce traffic and storage even further; see Commercial on the home page.
Because of the way UrBackup uses hard and soft links to create a standard filesystem view of the backed-up data, many utilities show the “wrong” value for the space used by a backup. They are following the links and reporting the space as if deduplication were not being used. Most of the ones that show the free space of the storage drive itself are correct. One could compare before and after values for the free space and compute the storage actually consumed for the backups done in that session. Again, see the Documentation for how UrBackup manages space.