It is a factor of Iowa's "pro-style" offense. I don't mean pro-style like it has TEs and FBs, that is not really what things look like in the pros (nor have they for a long time). Pro-style means that players must make decisions pre-snap and post-snap based upon what the defense is doing. Many current college systems, especially the super uptempo ones, do not rely upon the same sort of read and react, but rather have rigid assignments based upon play.
A pro-style has great flexibility; one play can potentially defeat a whole range of different defenses if the players make the correct reads and adjustments. The other system lacks that flexibility, which they generally make up for with a bigger playbook, which they can get away with because typically a coach calls plays from the sidelines and the players figure things out from their wrist-worn playbooks, decreasing the player-burden of playbook memorization. They also overcome the lack of flexibility by going at such a high tempo as to limit the defense's ability to recognize what they are doing and adjust to it.
The pro-style system put a lot of learning burden on the players. The other system almost amounts to the coach playing chess, with the players being the pieces.