What point do the speakers make when they discuss the materials used in the iceberg design?

Listen to a conversation between a student (S) and her architecture professor (P).
S: Yesterday I happened to be flicking through one of my roommate’s magazines when a striking digital image of an urban building caught my attention. The unusual form of the building, specifically the way its roof was shaped into several steep, sharp points, it was really unique. Kind of futuristic, you know? When I stopped and actually read the article describing it, I was even more intrigued! The team that’s proposing the design calls it an "iceberg."
P: Yes, I’ve heard about that. The iceberg design is a fascinating concept. Are you considering using that for your model project?
S: Yes, that’s exactly what I mean! It’s really cutting-edge.
P: It is. What you’re working with, essentially, is a building that really boils down to two components: a steel skeleton and also a flexible high-tech plastic fabric that encases the steel skeleton.
S: Yeah! I remember reading that. It’s supposed to function pretty much like a tent, right?
P: That’s correct! It uses hardly any building materials as a result. Fewer materials mean that it’s more environmentally friendly. Now, do you know why the iceberg was proposed?
S:No.
P: Well, it was the designer’s mission to create buildings that could be very quickly assembled to provide attractive retail space.
S: Hmm..., interesting.
P: You see, undeveloped city sites need to be effectively used; otherwise they might become a huge financial burden to the property owner. The owner has to continue to pay taxes on the land, even when it’s nothing more than an empty lot. So with their vision, they thought of putting up an iceberg. The property owner would rent out the space and that would help generate income for the owner.
S: Awesome! I’m pretty sure that the iceberg concept would be ideal for the project now.
P: Seems so. And you read about air beams in the magazine article, right?
S: Actually, I saw the term used a couple of times, but I didn’t quite understand the details.
P: Well, one reason that this type of building is able to morph into such unusual shapes and lean its walls at such extreme angles is that empty sections of plastic are sewn in, and these sections are then inflated with air. These inflated air beams make it possible to have different types of extensions on each building, like the pointed sections of the roof you mentioned. And they’re sturdy, solid, and still very light weight.
S: Ahh...I guess this is why they’re nicknamed "inflatable buildings."
P: That’s right, so they’re a feature critical to get right, ok?
S: Got it. I’ll make sure to get up to speed on that then.
P: Great! Oh, by the way, before you head off, are you going to be able to join the group for the field trip to the Frank Lloyd Wright house? I have to submit the names to the dean. It’s on the 20th, remember?
S: Oh, yes, the 20th. It’s on the syllabus, but you said that it was voluntary, right?