I started doing this years ago for two reasons. I liked the visual appeal, and it kept me from EVER having to sand the flats. Its so easy to finish a textured surface because you only have to finish the high spots. I do this at an 8" x 1" scotchbrite wheel on a speed controlled bench grinder. Literally, I can finish the flats on several knives per minute with this method. Almost all of my process is designed for efficiency, when I teach it, I call it 'the easy way'. Once I figured this out, I developed a technique to make the flats look like burnt skin, then named it 3D (for 3D burned) Spalted Steel. The name caught on and has helped me sell knives. I find naming things (models, features, whatever) on a knife helps them sell. The market likes to memorize the names. I learned that from watching Jerry Busse. So your answer from the perspective of my business is almost all of the above ideas. (I don't act like they are forged though. I named my business before I started selling knives. At that time I forged the blades. I quickly learned how much more efficient and repeatable it is (for me) to use the stock removal method. YMMV.)
Edited to add some pics: