I don't know, Mario, I kinda like the solitude the comes with diving. If I had on a headset, the Mrs. would ruin 75% of our dives, saying, "No, don't go there, stop that, and etc etc." I can see the benefits of it from a class standpoint and on advanced dives, like penetrations. But then again, Submariner has a good point about training in what you intend on using. And most new divers aren't willing to shell out the bucks for the gear. As far as classes go, I think the biggest advantage to be gain in a class by instructor and student, would be one on one instruction. I know that in today's "price conscious" world that it just isn't practicle in alot of cases, but still that would be the best way.
But I do see a future for comm gear. Probably some day in the near future it will become standard for charter boats to be equipped with it and all a diver has to do is provide their own headset.