> Why are all these tools DAGs? I don't understand your question. Perhaps the answer is that workflows naturally require data processing tasks to spawn collect

> Why are all these tools DAGs? I don't understand your question. Perhaps the answer is that workflows naturally require data processing tasks to spawn collections of child tasks when a parent task finishes, and conversely they are also require to spawn a child data processing task only after a collection of parent tasks finish executing. Therefore this requirement to fork and join tasks ends up being modelled as a directed acyclic graph of processing tasks.