Is it possible to backfill a materialized view? I'm maybe confused, but does this potentially replace a traditional data lake or is it specifically for streaming applications?
To your other question, we're currently well-suited for streaming applications. Moving forward, as we add support for features like persistence, we could certainly replace at least parts of a traditional data lake.
[0]: https://materialize.com/docs/sql/create-source/json-s3/