Dask is actually similar to spark in that it will let you compute outside of your computer over multiple machines.

Matt Rocklin (the dask creator) has put some effort into benchmarking across all these recently. You can see the presentation here: https://youtu.be/5YXiRl41DKA?si=5Pt9XQHp5Y1cG7tM

If you don't feel like watching a whole presentation, the main take away is local is faster, until it isn't.

Polars outperforms spark by a wide margin, until data size gets sufficiently large that things swap over.

Some operations can be performance sensitive without having scaling issues. So I guess those kind of jobs are great candidates for something like polars.