Are Striations On 1923 S Buffalo Nickel Natural From Hard Striking Or Manipulations From Polishing/Wh

Agree, both are caused by Die Deterioration. What you are seeing by the buffalos leg are metal flow lines. When a coin is struck, the metal moves across the die, filling the high points (devices). Over time, this wears on the die and creates groves in the dies surfaces called metal flow lines. They become more extreme the longer the die is in use. The same goes for the mintmark. Small details like the MM become mushier, widened, or convoluted as you described. Sometimes this also creates a doubling effect known as Die Deterioration Doubling.

Buffalo nickels are known for their extensive die problems, especially branch mints (San Francisco more so). Excessive die use, reused dies, and overpolishing plague this series. The later creating a number of well known varieties (2 feather and 3 leg/ 3 half leg varieties).

Edit: Die Deterioration in and of itself carries no premium. Well struck, earlier die state examples tend to bring a premium. Extreme examples of Die Deterioration do however make an interesting conversation piece, especially for us die hard buffalo fanatics