SAR GRD preprocessing workflow necessity

I was working on Sentinel 1 SAR GRD (EW mode) imagery from Copernicus when I came across this workflow here.

Is it necessary for GRD products to pass through all steps of this workflow before they can be used?

For context, I’m looking into applying segmentation and classification algorithms on SAR imagery and was wondering if this workflow is necessary.

I’m new to SAR image processing.