How does xBR scaler work?

Could it be used to interpolate other kind of data? Because it gives vector-art quality results from low-res images: http://www.youtube.com/watch?v=htdi5jc3Ijc

that is compared to all other resampling algorithms, you can find in math books.

Why do people bother with these edge detection upscale filters? they always look shit compared to the actual pixels.