But rsync is widely available, usually installed by default on linux or unix-like systems. You can just use it.

Borg is available for download as a standalone binary, easily dropped onto any Linux system even with very limited privs. And in the repos of every distro easily installed and kept up-to-date.

By avoiding that one step and using rsync instead, you're resigning yourself to "send 600MiBs" over the network for every tiny config change. Not a good trade-off.