There is no feature gap between the pandas backend and our default DuckDB backend, and DuckDB is much more performant. pandas DataFrames will still be available as format for getting data to and from Ibis, we just won’t support using pandas to execute queries.
Most of the rationale below applies to the Dask backend since it has so much in common with pandas. Dask is a great project and people should continue to use it outside the Ibis context.
Way back in the early days of Ibis, there was only one backend: Impala. Not everyone used Impala (mindblowing, we know), and so it wasn’t too long until the Postgres backend was added (by the inimitable Phillip Cloud).
These two backends were both featureful, but there was a big problem with adoption: Want to try out Ibis? You need to install Impala or Postgres first.
Not an insurmountable problem, but a LOT more work than “just pip install <newthing>” – which prompted the question, how can a prospective Ibis user take the API for a spin without requiring a DBA or extra infrastructure beyond a laptop?