I imagine this would be a really good boon to the stage set industry. You could design intricate sets hopefully with less cost, and more speed?

il futuro è già arrivato!

My personal, subjective and rude opinion: Not pretty. And while technologically impressive, it's actually kind of lame.
Even average stone masons have way more feel for shapes and expressions than whoever went crazy with his CAD software to make this thing.
And the "impossible to make by any other means" thing: Alright, we get it. 3D printers can do that. Now get over it. And no, bigger is not better.

this is brilliant and would love to see it up close and the production stages.

@BeWalt
I believe the point was to generate extremely complex surfaces in an architectural setting. And bigger is better, if there is no significant loss of resolution. As most industries have yet to really embrace the significance of 3D printing, I think it is essentially required to pound it into people's heads until they realize "Wow, this is actually significant, and is changing the world". Sometimes a slightly different aspect of this changes peoples perspectives. Why don't we all live in Frank Lloyd Wright houses? Oh yeah, all that hand crafted customized brickwork (depending on which Wright home you want to replicate) required huge labor input. Hmm, maybe if I could design my brick pattern, and send it to my local architectural print shop, I could have whatever custom stonework I like. Would this have an impact on the architectural industry? I think so.
We are used to the constraints of mass production. It is infinitely more expensive today to make 1 off designs because making one of anything bears the entire design cost, and all of the tooling costs, and all the ...
3D printing enables a totally different different cost model. Mass production theoretically amortizes the entire production cost over a huge number of parts, eventually driving the end cost down to a small incremental amount above the bare material cost plus margin. Therefore all consumer goods MUST be mass produced to be economical.
These new technologies are extremely disruptive. Now you still have to amortize the cost of the 3D printer over its lifetime production, but consider the implications if I can now design a custom stone walkway that is curved. I don't need to start with rectangular blocks, cut them to fit, make compromises related to practicality. The current norms are all based on bending to the needs of the manufacturing process, and these emerging technologies will change EVERYTHING. I can't wait.

Transporting the result to site seems ridiculous. Transport the printer, and print on-site - now that makes sense.
Sandstone also seems silly. Here's a material that's both beautiful, and at least an order of magnitude stronger than concrete: " Composition for the production of artificial marble or granite ": Expired US Patent 5280051
Made, I must add, from ordinary sand too.

Just think! You could design the entire house room by room, adding things like cornices, shelves, alcoves, kitchen benches (just paint with epoxy for waterproofing and no dust) and all that fiddly stuff! The popular stone or marble-look would be there as you print!

My first thought is that this technology would be fantastic to repair cathedrals or create some of those amazing intricate Hindi temples.
But that's just predicated on what these gentlemen created--the possibilities just seem limitless.
But I think the statement: "There is no longer a cost for complexity. No cost for ornament. No cost for individuality." WILL encourage architects, artists and designers to push some boundaries. Which is exciting despite BeWalt dour reaction.

Download a 3D scan of a famous room and line your loungeroom walls with it.

It looks like the main 'big head' room in the Prometheus film. The artist Giger could have a lot of fun with this!
Maybe they should think about painting it to give it more depth. A bit of gold leaf would make a lot of difference.