That’s fair. If the requirement is “post-quantum reusable addressing as the final design”, then ECDH-based RPA is not the endgame.
But I think these are two different timelines.
Today, BCH still uses secp256k1. If secp256k1 becomes practically unsafe, the problem is much larger than RPA: signatures, wallets, existing coins, address reuse assumptions, and migration rules all need to change.
Until that migration path exists, I think current-era privacy/reusable-address designs are still worth evaluating. RPA may not be the final PQ answer, but it can still be a practical workload for today’s BCH ecosystem — especially for mobile/L1 usability.
So I’d separate the questions:
- What can improve privacy and reusable-address UX today under the current secp256k1 model?
- What should replace that model in a future PQ migration?
Both are important, but I wouldn’t block current privacy work on a PQ design that the ecosystem cannot yet deploy or test in practice.