O.K., here's a super chiming in.
Are scruffy bunkers easier or more difficult to maintain?
Standard GCS answer, "It all depends".
If you have sandy soils in a benign climate with some wispy fescue, then the bunker will look after itself.
If you have bermdagrass in a tropical rainforest, then you will have your work cut out for you, either way.
I manage a course where the "scruffy look" would fit perfectly with the architecture, but we don't do it. We've tried, but we are cursed with a rich, clay, topsoil, a mildly cool climate with plenty of rain, and pasture grasses galore. Wherever we let the grass grow up, it quickly becomes an impenetrable, ball-eating, matt. So with a few exceptions for out-of-the way areas, we keep the bunkers manicured, mowed and trimmmed around the edges.
To achieve the proper scruffy look here, we would need to change over the soil around the bunkers, and re-seed with fescues. But for a membership averse to disruptions, this is more trouble, and much more expensive, than carrying on with the present maintenance.
I remember visiting Las Vegas a few years ago, at Royal Links, where they were attempting to emulate links style holes, and there was a woody weed called "salt cedar" that was throwing them fits.
So bunker maintenance is a function of various factors, including climate, soils, species, budget, and golfer expectations.