Other than aesthetics and providing essential habitat for a
very select number of organisms, sand serves
no purpose that can't be accomplished another way. That's the truth.
I'm not saying it's necessarily any worse than any other approach - that's your opinion to form. Only that it only serves a purpose if it serves you. There isn't a critter I haven't seen in my BB tank that I saw in my DSB tank. That includes many kinds of worms. They live in rock, too.
There is also an argument that whatever microorganism niche is being provided by the sand only benefits the sand anyway. How much plankton is feeding your tank from these niche critters? We've already stressed the skimmer's importance - and it's taking much of this potential food out. IMO, it's a completely irrelevant factor inasmuch as someone else thinks it's a benefit. You can't prove it either way and IMO there's nothing essential lacking from my sandless tank related to this "factor". Some people gravitate toward the idea that they are able to create more "natural" food for their tank. I see no beneficial evidence either way and as many cons as pros.
Personally, I don't want the added biomass that sand brings with it. Which is not to say that it's needed for most organisms in a reef tank, but rather that it just provides more habitat space than no sand at all. That some folks see more stability with sand vs. BB is hard for me to grasp. There's something else at play here, since any sand is another living, respiring organism. How that
adds stability is your case to make.
In the end, it
is a silly argument, but it seems like people will never tire of defending their methods (myself included) which often has a component of detraction to the alternatives. As for myself, never sand again.
And Greg, my website has tons of pics of my tank's evolution from DSB to SSB to BB (well, faux sandbed). I'll have current ones up by the weekend I hope, but there are some from January up there. I've never had a tank funtion better - using the exact same equipment. Maybe it's just my "time".