Not even that. An attacker with local root can just extract the wireguard keys from process memory, or use the TPM to decrypt the state file like Tailscale would.
The only scenario where it helps is a local attacker who can read the state file on disk, but is not full root. Kinda unlikely on Linux, but could happen on Windows.
The only scenario where it helps is a local attacker who can read the state file on disk, but is not full root. Kinda unlikely on Linux, but could happen on Windows.