I've seen some Classic McEliece deployments, too. Well, I know of only one: Mullvad.

https://github.com/mullvad/mullvadvpn-app/blob/main/talpid-t...

Some helpful, perhaps valid context is that lattice-based cryptography was a contender even before PQC became a thing (NTRU being the obvious example).

Really the only point I'm trying to make here is that there's nothing eyebrow-raising about systems using lattice crypto; after IFP/FFDLP stuff like RSA and ECDLP, lattices are maybe the next most mainstream approach to constructing asymmetric systems.

I'm late to the party, but McEliece codes have also been around for a very long time, predating AES by a fair margin. The biggest problem with them is that the public keys are gigantic and the private keys are very large - even bigger than the keys used in lattice-based cryptosystems. This has caused them to always be a sort of fringe form of cryptography.

The good part is that McEliece codes are based on a proven NP-hard algorithm, so cracking them in polynomial time needs P = NP.