Why "Cryo" anything?

Ok. So far, I have yet to think of a good explanation for "Cryo" treatment to enhance anything. Can someone explain this to me?

For background, I have a Master degree in Material Science Engineering. Here is my explaination why just "cryo" won't work.

At room temperature, the metal is already solid or frozen. Freezing it further won't do much. Most metals requires high temperature to cause any change in the microstructure or grain size/orientation/distribution. Simply freezing it for a few minutes will not change how it operates after the metal returns to room temperature.

Eric