This project reminds me a lot of Dask https://dask.org/. A library that allows delayed calculation of complex dataframes in Python.
https://github.com/asavinov/prosto
However, Prosto allows for data processing via column operations in many tables (implemented as pandas data frames) by providing a column-oriented equivalents for joins and groupby (hence it has no joins and no groupbys which are known to be quite difficult and require high expertise).
Prosto also provides Column-SQL which might be simpler and more natural in many use cases.
The whole approach is based on the concept-oriented model of data which makes functions first-class elements of the model as opposed to having only sets in the relational model.
Hamilton wouldn't replace Dask. Instead Hamilton could use Dask, we even have a prototype PR to do so.