WireGuard is a VPN protocol. There are roughly two kinds of VPN. Those that you use to hide who you are when accessing the Internet (route all your traffic via the VPN to an exit node) and those that you use to build a private network over a public one for e.g. a company or other organization.
Wiretrustee seems to be for generating a private org network. Could be personal, work, circle of friends or anything. Most traditional work VPNs have one or more nodes that all traffic pass through and that all connect to. A mesh VPN instead allows VPN peers to send traffic directly to each other over the public Internet. There seems to be a central coordination/signaling server, as with tailscale, headscale and innernet. But that is mainly used to find where the traffic should be sent, not for sending all traffic through it.
Wiretrustee seems to be for generating a private org network. Could be personal, work, circle of friends or anything. Most traditional work VPNs have one or more nodes that all traffic pass through and that all connect to. A mesh VPN instead allows VPN peers to send traffic directly to each other over the public Internet. There seems to be a central coordination/signaling server, as with tailscale, headscale and innernet. But that is mainly used to find where the traffic should be sent, not for sending all traffic through it.