They're for tables and doing table-ie things: an imperative programming method for the same tasks people use Excel or SQL for. This dovetails nicely with most

They're for tables and doing table-ie things: an imperative programming method for the same tasks people use Excel or SQL for. This dovetails nicely with most data science-ie tasks, like statistical analysis, engineering features, simple machine learning techniques (the tables can be easily transformed into numpy arrays), and plotting results. You can use them any time you feel the need to do table manipulations on non-insanely-large data: aggregate, transform, combine, split, reshape, join...