I wonder at which scale spark fits into this picture and what the tradeoffs / benefits would be
one benefit for me personally: you should be able to move from local dev to cloud more easily.
I guess it comes down to how well written the distributed workflows are, there's a lot to get wrong, but in theory it should be able to achieve very impressive numbers.
My reasoning behind this is Dask, which uses Pandas under the hood being capable of better benchmarks than Spark, I think this is partly some good optimisations, but also simply that pandas is faster than spark's row based model. Duckdb is on some benchmarks more than 10x faster than pandas, you can see where this is going. . .