QoS allows us to prioritize traffic. This may be to give high priority treatment to the traffic coming from, or destined for, a business application, or to ensure that voice and video traffic are prioritized. Both voice and video traffic are sensitive to delay and jitter, so making sure that these receive priority is important for the user experience.
While ACI may not be designed with voice and video protocols in mind, there is no reason that the tenants are not running them or have other demands for QoS, such as preserving class of service (CoS) markings on traffic transiting through the fabric.
