When I first started with chickens over 20 years ago I was told, and later read, that cracked corn, from the elevator, was cracked because they removed the germ and put it into cornmeal or another corn feed mix. It would increase the amount of protein in the feed. This may be outdated, or sometimes done and sometimes not.
I never use cracked corn anyway because as soon as you break the seed it starts loosing nutrition. Obviously if you roll it/crack it yourself it isn't sitting on the shelf for very long. It is supposed to be easier to digest because of the smaller particles, but you also get more dust.