Kiono uses AWS Organizations for AWS account creation. The OU structure in Kion is completely separate from the OU structure in AWS Organizations. You can choose to use your AWS Organizations OUs if you are using Kion - they are designed to be complimentary.
AWS Organization OUs allow you to apply Service Control Policies (SCPs) to groups of AWS accounts at an account level that limit even Administrators from using certain AWS services. Kion allows you to apply Cloud Rules to Kion OUs, which apply IAM policies to all roles managed by Kion. Kion then provides the ability to request exemptions to those policies. This allows for a more granular control of permissions.