Rsync + a bash script is horrible to get going in a mobile device. (What is the fault of the mobile OSes, and if you can get by with a less hostile one, great for you.) Those open-core ones put some work on it.
Taking a picture with my phone and having it show up on my computer in 5 seconds is pretty close to magic in terms of file sharing.
Completely free, andno central server to introduce "age verification" or whatever.
Sc is very, very cool but you must sync both ways every time, so after some time, if your phone runs out of space, things get hard. The "do not erase on 'server'" setting is pretty well hidden and claimed not to be supported and can break things.
Also, for "one way sync", with super easy setup, i have not found an alternative for btsync (now called resilio). SC is too clunky to set up the client and in this case, running Nextcloud server + setting up clients is crazy complex. TIL about Unison and will try it out...