All nodes on Mycoria end up in one huge network. The PN in VPN is for "private network", so I couldn't say this can do anything that a regular VPN can do.
Any node on the network can find my node via mDNS discovery and access any services which I expose. Services need to be secured in the same way I'd do on the public Internet, and not in the same way I do on a trusted private network between a few trusted nodes.
That said, I do believe this is useful in a lot of scenarios where a VPN might be too much work to set up. While one does need to ensure that all services do authentication, the encryption part is valuable, and this does ease exposing services from non-routable nodes with no consistent public IP.
Mycoria is secure by default: It has an integrated firewall that only allows access from explicitly defined addresses, or, optionally from anyone in the network.
Also, multicast is completely disabled on Mycoria.
Any node on the network can find my node via mDNS discovery and access any services which I expose. Services need to be secured in the same way I'd do on the public Internet, and not in the same way I do on a trusted private network between a few trusted nodes.
That said, I do believe this is useful in a lot of scenarios where a VPN might be too much work to set up. While one does need to ensure that all services do authentication, the encryption part is valuable, and this does ease exposing services from non-routable nodes with no consistent public IP.