A VPN is point-to-point. You fire up the client on your laptop and connect to a server. That server is usually also acting as a bridge into a network. It gives

A VPN is point-to-point. You fire up the client on your laptop and connect to a server. That server is usually also acting as a bridge into a network. It gives your machine a presence into that other well defined network. ZeroTier is an overlay network. What is does it create a new encrypted network, with it's own address space and everything, on which you can connect through the controller (a default one is provided by ZeroTier). It doesn't matter where the nodes are. If it detects that two nodes are on the same LAN it's going to route the traffic directly. The overlay network is encrypted all the time, even when it goes over your LAN.