...
Can anyone tell me if folding papercraft buildings is any faster than making terrain?
...
Neldoreth, print-and-cut paper terrain is always faster to make, but even a simple castle wall made with white styrofoam and a very simple paint scheme stands much better in the games table, because of the 3D effect, IMHO.
Can you imagine your wonderful Prancing Pony done with a printer and a pair of scissors? 
Well, Terraclips doesn't require a printer and a pair of scissors, as far as I can tell.

'No printing, no cutting, no painting,' from their site. However, seems like it might cost as much or more, and if you have the wicked talent Neldoreth has, certainly not as satisfying, especially to those of us lurkers. ;->=
Doug