Well, I think its obvious that they sacrificed longevity for size in that system. Although I personally dont see why they couldnt have still used a smaller version of the full-size USP two-spring system.
It was a factor that left me buying the full size USP45. Does it make the pistol a bad pistol? I wouldnt think so... after all, every other pistol out there doesnt have one!
Also, one could suppose that it lets them use a slightly less stiff primary recoil spring, thereby insuring reliable cycling even on underpowered loads.
J.T.
as usual, FWIW, IMHO, YMMV and all that