After skimming both the GitHub and the protocol specification for rosenpass, I still have no idea what benefit it provides on top of wireguard and therefore why I should use it.
> Rosenpass is a key-exchange protocol using techniques that are secure against attacks from quantum computers. It achieves the same security guarantees as WireGuard, using two strong post-quantum key exchange methods – Classic McEliece and Kyber.
> To use Rosenpass, you don't have to get rid of WireGuard; Rosenpass handles post-quantum security, WireGuard handles pre-quantum security and high-speed data transmission.
I saw some references to post-quantum security, but I also saw references to something called "Post-Quantum Wireguard" so it seemed like that was handled by some other project, or at best some sub-component of Rosenpass.
Wireguard has a pre-shared key that can essentially get 'added to' the base key, making it more secure. Rosenpass effectively just makes these PSKs and trades them in a way that makes it quantum secure.
Basically it should be a part of base wireguard, but for now it's a good addition.