Hey Louis - the Argonauts have a "custom monocoque" construction.
Tyler from BIkeRumor did a great job of breaking it down in his factory visit:http://www.bikerumor.com/2013/01/28/inside-look-at-argonaut-cycles-unique-full-custom-carbon-monocoque-road-bikes/
I've heard inside industry types from other top brands refer to the construction as "internally lugged".
Either way, the visible wrapped element is indeed structural from what I understand.
Like most handbuilt carbon framesets, there is an element of ride quality tuning through the wrapped areas, aka "lug" or cluster locations.
Those areas being BB, "Seat-collar", and Headtube - really where the stiffness elements of a bike are most important.
My quick ride on this bike had me thinking Ben has figured out an amazing way to generate flex from his ISP as well.
Over some crappy stretches of local road, the bike was super-composed and very smooth.
Yet when my 6'2" ass got out of the saddle to hammer, the bike felt solid where it needed to be.
Overall I was miiiiiighty impressed with our first Argonaut build.
Not cheap, but build quality, weight and ride impressions were all top notch and the customer was very happy.