Why Syncthing breaks all connection after adding a folder?

When adding a sync folder to Syncthing, all of it’s connections will break, then they reconnect. Why Syncthing will do this, isn’t it better to keep the connections while adding a folder?

The folders are exchanged as part of the connection handshake. This is simpler, and almost never matters.

Ok, I thought the handshake and the data transfering are seperated.