Device-level management allows for more granular control over the specific settings and configurations of individual network devices. This is beneficial in scenarios where fine-tuning of device settings is required, and where certain configurations may not be exposed or supported by the overarching controller. Controller-level management, on the other hand, abstracts many device-specific settings to provide a more uniform and simplified management interface, which may not support all the detailed configurations available at the device level.
References:
* Cisco DevNet: Device vs. Controller Management