[AI Man]

SAMW
Well I do think the reef in some ways would be less stressful and certainly more natural, but at what cost to it's currently healthy inhabitants?

Dead, live rock or even PVC pipes can provide a habitat for fish during quarantine. As well as a dimly lit tank to calm them as they get used to captivity.

This environment (bare tank) couldn't be too bad otherwise clownfish would not feel comfortable enough to spawn in bare tanks with a plant pot. I think water quality is the most important factor over aesthetic surroundings.

Many fish are shy feeders at first and would fail to compete in a tank full of existing fish.
I don't understand why you feel it wouldn't help? Hopefully the conditions in a quarantine tank are smaller and maybe a little more easily adjusted.
I often see tanks were existing fish have adjusted over time to poor conditions, and newly added fish are shocked.
The main reason is medication and water changes are more practical in a small aquarium. Also Medications that are not reef safe can be used, medications and medicated food can more accurately be administered, There is no stressful aggression or territorial behaviour to further stress the fish.