For each session. Keys are rotated frequently, so a lot of noise could be produced. The only and one address is a good strategy for anti fingerprint though, but it is not easy to achieve for WG tunnels and pure L3 routing.
Personally I don't really get their multi hop when you connect on a predefined port on an ingress server to get redirected to egress in a different region. Easy guessable for a powerful observer.
Anyway any VPN is only an encryption tool, not an anonymizer.
A key selling point of WireGuard is it can roam between networks very well, without interruption to the connections within tunnel. Rotating IP address once you roam to another network (or just flaky wifi) ruins this.
Personally I don't really get their multi hop when you connect on a predefined port on an ingress server to get redirected to egress in a different region. Easy guessable for a powerful observer.
Anyway any VPN is only an encryption tool, not an anonymizer.