To me they seem like the pythonic version of dbt! Instead of yaml, you write Python code. That, and a lot of on-the-fly computations to generate an optimized workflow plan.
This IS a runtime.
You import bauplan, write your functions and run them in straight into the cloud - you don't need anything more. When you want to make a pipeline you chain the functions together, and the system manages the dependencies, the containerization, the runtime, and gives you a git-like abstractions over runs, tables and pipelines.