But you don't have to write map-reduce jobs at all? You can just write SQL queries or Pandas programs, and they automatically get parallelized by Databricks. Databricks is a data warehouse (just like Snowflake).
In a twist, pandas programs don't get parallelized on Spark. Someone had to go and write a parallel layer that duplicated the pandas API, because otherwise you ended up with the entire pandas program executing on a single executor.