C
Cliff Underside
Well, as i've shown above, it seems that it doesn't add blur anymore, with smoothness set to 0% that is. But it certainly did at some point.
xPikYx
My native resolution is 768p so any extra blurriness beyond what i've set intentionally (such as FXAA) is a negative for me. I always try to have the cleanest possible image, hence why I didn't like DSR even with 0% smoothness and chose to use custom resolutions instead. But each to their own... There's many different monitor and games out there, you never know what will give the best results for your taste.