The proposal doesn't mention it, but some Zero Knowledge Proof schemes are post-quantum secure. Unfortunately, this proposal uses a ZKP that is not post-quantum secure (i.e. it uses ECC). If the proposal were modified to use a post-quantum secure ZKP, then I think it would be even more attractive than it already is.

The author has inadvertently revealed a path to adding PQC to Bitcoin that doesn't require a hardfork.