We love ParadeDB and their team. Their primary focus is search (Elasticsearch on Postgres), but they also have the pg_analytics Postgres extension (foreign data wrappers and embedded DuckDB).

The biggest difference is in a Postgres extension vs a separate OLAP process. We want to allow anyone with just Postgres to be able to perform analytics queries without affecting resources in the transactional database, building and installing extensions (might not be possible with some hosting providers), dealing with dependencies and their versions when upgrading Postgres, manually syncing data from Postgres to S3, etc.