An interesting article overall, but I think authenticating a user based on their IP address is probably the worst security advice I've seen. It's probably ripe for attack with ARP poisoning, IP spoofing, etc.
It only authenticates it _after_ all the WireGuard bits. So it's not really auth by IP address, but auth by wireguard key identity, from which we know your identity. There's no IP spoofing possible. And ARP isn't even in the picture for an L3 protocol.
You can configure ACLs. By default devices that aren’t tagged with an ACL tag are available to other devices authenticated by the same user. If you tag a device, you have to write explicit ACLs to permit access from other users/devices.
