>>stavro+(OP)
Most of us do not have IDS/IPS/DLP tooling in our home networks, nor do we have a 24/7 on-call SOC team monitoring their SIEMs dashboards.
Google and Microsoft provision this stuff, even for consumers, with secure authentication and good protections.
>>AStone+C
Syncthing is peer to peer, the files are already on the device. There's no way requiring one more device to be secure (the server) is better than not requiring it.