I think they are decently well enough integrated now. Rather than starting a dask cluster, you can run dask on a Ray cluster

https://docs.ray.io/en/master/dask-on-ray.html

Dask itself (and its commercial entity Coiled) seems to be investing heavily in the PyData/ml library ecosystem. I feel like it's about time until they reach feature parity, which would be a huge win for existing users of the PyData stack.