Are you sure those are faster? The only obvious slowdown in Syncthing compared to them is the initial file scan. The file transfer saturates the pipes like any other option. If you meant the file scan overhead, then we're on the same page. ☺️
At the same time Syncthing is ultra resilient and will auto-restart and continue syncing no matter what happens to the network connection or the hosts during transfer without intervention. This is why I stopped using rsync for initial transfers. When the initial transfer would take a week over the Internet, using Syncthing and swallowing the initial scan is nice because you don't need to look after it.