After creating a HAIL MatrixTable and saving your cleaned dataset, you may no longer want to run a dataproc cluster and instead use a standard environment. You can load and run HAIL commands in the standard environment without the cluster, but if you plan to read directly from the GCS bucket, you will need to install the Google Cloud Storage Connector. You can find install instructions here.
The benefits of moving to a standard environment are utilizing less computing resources which cuts down on computing cost.