Hey author, here, so yes its not the most recent technique, but when coupled with rescoring like we propose it can be a simple speed up for linear scans. It also a pure SQL solution and requires no indices. It benefits from being easy to update and not being mem bound. We recognise all the issues with it and pros in the final section. We're defn not claiming this is ground breaking - more a useful technique which is easy to replicate in SQL.
Pinecone https://www.pinecone.io/learn/series/faiss/locality-sensitiv... seem to promote as a viable approach.
We defn don't consider this to be the final solution for ANN and hence are investing in other graph based techniques - https://clickhouse.com/docs/en/engines/table-engines/mergetr...